v0.15.0 password recovery, phone layout, CLI pager, embed policy fixes

.github/workflows/test.yml

@@ -80,11 +80,13 @@ jobs:
         run: npm install && npx playwright install --with-deps chromium
       - name: Start the test server with the web client
         run: |
-          WEB_PORT=9090 LOG_LEVEL=info test/run-test-server.sh bin/chess-server > server.log 2>&1 &
+          WEB_PORT=9090 MAIL_DIR="$RUNNER_TEMP/chess-mail" LOG_LEVEL=info test/run-test-server.sh bin/chess-server > server.log 2>&1 &
           for i in $(seq 1 60); do curl -sf http://localhost:8080/health && break; sleep 1; done
           curl -sf http://localhost:8080/health
       - name: Run the web client tests
         working-directory: test/e2e
+        env:
+          CHESS_E2E_MAIL_DIR: ${{ runner.temp }}/chess-mail
         run: npm test
       - name: Server log
         if: failure()

README.md

@@ -30,6 +30,8 @@ Go backend server providing a RESTful API for chess gameplay with user authentic
 - Authenticated stored-game listing with cursor pagination and filters
 - Configurable structured debug logs for persistence, cleanup, and engine work
 - User management with secure Argon2id password storage and scoped JWTs
+- Password recovery by email (SMTP relay, or a directory of `.eml` files in
+  development) and administrative reset links
 - Self-service account deletion: claims and names are cleared from stored games
 - Static, CGO-free binaries (cross-compiles for FreeBSD)
 - Scripted deployment: FreeBSD jail (rc.d) or Linux (sandboxed systemd unit)
@@ -134,9 +136,12 @@ their last activity.
 # List all users
 ./chess-server db user list
 
-# Update password
+# Update password (a forgotten one too); without -password it prompts
 ./chess-server db user set-password -username alice -password NewPass456
 
+# One-time reset link to hand to the person (what the recovery email carries)
+./chess-server db user reset-link -username alice -url https://example.com/chess/web-client/
+
 # Update email
 ./chess-server db user set-email -username alice -email newemail@example.com
 
@@ -175,7 +180,7 @@ The chess server includes an embedded web UI for playing games through a browser
   export FEN and PGN at any ply, and shareable links
   (`?replay=<gameId>&ply=<n>`)
 - Server and storage health in the top bar
-- Accounts: register, sign in, delete
+- Accounts: register, sign in, forgotten-password recovery by email, delete
 - Responsive layout, board beside or above the panel
 
 Access the UI at `http://localhost:9090` when server is running with `-serve` flag.

cmd/chess-client-cli/main.go

@@ -35,8 +35,14 @@ func runClient() (restart bool) {
 		Verbose:    false,
 	}
 
-	// Initialize simple input scanner
+	// Initialize simple input scanner; the pager reads from it between screens
 	scanner := bufio.NewScanner(os.Stdin)
+	s.ReadLine = func() (string, bool) {
+		if !scanner.Scan() {
+			return "", false
+		}
+		return scanner.Text(), true
+	}
 
 	display.Println(display.Cyan, "Chess Debug Client")
 	display.Println(display.Cyan, "API: %s", s.APIBaseURL)

cmd/chess-server/cli/cli.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"net/url"
 	"os"
 	"strings"
 	"syscall"
@@ -12,6 +13,7 @@ import (
 	"time"
 
 	"github.com/lixenwraith/chess/internal/server/replay"
+	"github.com/lixenwraith/chess/internal/server/service"
 	"github.com/lixenwraith/chess/internal/server/storage"
 
 	"github.com/google/uuid"
@@ -40,7 +42,7 @@ func Run(args []string) error {
 		return runVerify(args[1:])
 	case "user":
 		if len(args) < 2 {
-			return fmt.Errorf("user subcommand required: add, delete, set-password, set-hash, set-email, set-username, list")
+			return fmt.Errorf("user subcommand required: add, delete, set-password, set-hash, set-email, set-username, reset-link, list")
 		}
 		return runUser(args[1], args[2:])
 	default:
@@ -303,6 +305,8 @@ func runUser(subcommand string, args []string) error {
 		return runUserSetEmail(args)
 	case "set-username":
 		return runUserSetUsername(args)
+	case "reset-link":
+		return runUserResetLink(args)
 	case "list":
 		return runUserList(args)
 	default:
@@ -310,6 +314,48 @@ func runUser(subcommand string, args []string) error {
 	}
 }
 
+// runUserResetLink prints a one-time password-reset link for an account, the
+// same link the recovery email carries, for an administrator to pass on when
+// the server sends no mail or the account has no email. It works for an hour
+// and replaces any pending link.
+func runUserResetLink(args []string) error {
+	fs, dsn := newFlagSet("user reset-link")
+	username := fs.String("username", "", "Username")
+	userID := fs.String("id", "", "User ID")
+	publicURL := fs.String("url", "", "Web client address the link opens, e.g. https://example.com/chess/web-client/ (required)")
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+	base, err := url.Parse(*publicURL)
+	if *publicURL == "" || err != nil || base.Scheme == "" || base.Host == "" {
+		return fmt.Errorf("-url must be the web client's absolute address")
+	}
+
+	store, err := openStore(*dsn, true)
+	if err != nil {
+		return err
+	}
+	defer store.Close()
+
+	targetID, err := lookupUser(store, *username, *userID)
+	if err != nil {
+		return err
+	}
+	token, hash, err := service.NewResetToken()
+	if err != nil {
+		return err
+	}
+	now := time.Now().UTC()
+	if err := store.CreatePasswordReset(storage.PasswordResetRecord{
+		UserID: targetID, TokenHash: hash, CreatedAt: now, ExpiresAt: now.Add(service.PasswordResetTTL),
+	}); err != nil {
+		return fmt.Errorf("failed to create reset: %w", err)
+	}
+	fmt.Printf("Reset link for %s, valid until %s (one use):\n%s\n",
+		abbreviateID(targetID), now.Add(service.PasswordResetTTL).Format(time.RFC3339), service.ResetLink(base, token))
+	return nil
+}
+
 // readPassword prompts on the terminal without echo.
 func readPassword(prompt string) (string, error) {
 	fmt.Print(prompt)

cmd/chess-server/main.go

@@ -5,6 +5,7 @@ package main
 import (
 	"context"
 	"crypto/rand"
+	"errors"
 	"flag"
 	"fmt"
 	"log"
@@ -16,6 +17,7 @@ import (
 
 	"github.com/lixenwraith/chess/cmd/chess-server/cli"
 	"github.com/lixenwraith/chess/internal/server/http"
+	"github.com/lixenwraith/chess/internal/server/mail"
 	"github.com/lixenwraith/chess/internal/server/processor"
 	"github.com/lixenwraith/chess/internal/server/service"
 	"github.com/lixenwraith/chess/internal/server/storage"
@@ -58,6 +60,17 @@ func main() {
 		jwtFile     = flag.String("jwt-secret-file", "", "File holding a stable JWT signing key, mode 0600, at least 32 bytes (default $CHESS_JWT_SECRET_FILE)")
 		dbCleanup   = flag.String("db-cleanup", "off", "Hourly integrity sweep of stored games and accounts: off, report (log only), or delete")
 
+		// Password recovery by email: a transport (SMTP relay, or a directory
+		// of .eml files for development) and the web client's address, which
+		// the emailed link opens. Without a transport, recovery is off.
+		smtpHost     = flag.String("smtp-host", "", "SMTP relay for password-reset email (recovery is off when empty)")
+		smtpPort     = flag.Int("smtp-port", 25, "SMTP relay port")
+		smtpUser     = flag.String("smtp-user", "", "SMTP user name (optional; the password comes from -smtp-password-file)")
+		smtpPassFile = flag.String("smtp-password-file", "", "File holding the SMTP password, mode 0600")
+		mailFrom     = flag.String("mail-from", "", "Sender address of server email, e.g. \"Chess <chess@example.com>\"")
+		mailDir      = flag.String("mail-dir", "", "Write email to .eml files in this directory instead of sending (development)")
+		publicURL    = flag.String("public-url", "", "Web client address that emailed links open, e.g. https://example.com/chess/web-client/")
+
 		// Web UI server flags
 		serve     = flag.Bool("serve", false, "Enable web UI server")
 		webHost   = flag.String("web-host", "localhost", "Web UI server host")
@@ -165,6 +178,27 @@ func main() {
 	}
 	svc.SetIntegrityMode(integrity)
 
+	// Password recovery needs mail and the client's public address.
+	sender, err := mail.Config{
+		SMTPHost: *smtpHost, SMTPPort: *smtpPort, SMTPUser: *smtpUser, SMTPPasswordFile: *smtpPassFile,
+		Dir: *mailDir, From: *mailFrom,
+	}.Build()
+	switch {
+	case errors.Is(err, mail.ErrNoSender):
+		log.Printf("Password recovery disabled (no -smtp-host or -mail-dir)")
+	case err != nil:
+		log.Fatalf("Invalid mail configuration: %v", err)
+	case store == nil:
+		log.Fatalf("Password recovery (-smtp-host or -mail-dir) requires a database (-dsn)")
+	case *publicURL == "":
+		log.Fatalf("Password recovery requires -public-url, the web client address that reset links open")
+	default:
+		if err := svc.SetMailer(sender, *publicURL); err != nil {
+			log.Fatalf("Invalid -public-url: %v", err)
+		}
+		log.Printf("Password recovery enabled: %s; links open %s", sender.Describe(), *publicURL)
+	}
+
 	// Start cleanup job for expired users/sessions
 	cleanupCtx, cleanupCancel := context.WithCancel(context.Background())
 	cleanupDone := make(chan struct{})

deploy/freebsd/rc.d/chessd

@@ -18,11 +18,25 @@
 #                          Default: ${chessd_home}/jwt.key
 # chessd_trusted_proxies:  Reverse-proxy address(es) whose X-Real-IP header is
 #                          trusted as the client address. Default: none
+# chessd_public_url:       The web client's public address, which emailed links
+#                          open. Default: none
+# chessd_smtp_host:        SMTP relay for password-reset email (the mail jail).
+#                          Unset leaves password recovery off. Default: none
+# chessd_smtp_port:        Relay port. Default: 25
+# chessd_smtp_user:        Relay user name, when the relay authenticates
+#                          this host. Default: none
+# chessd_smtp_password_file: File holding that user's password, mode 0600.
+#                          Default: ${chessd_home}/smtp.secret when it exists
+# chessd_mail_from:        Sender address of server email. Default: none
 # chessd_flags:            Additional flags passed to the binary. Default: ""
 #
 # Add the following to /etc/rc.conf to enable:
 #   chessd_enable="YES"
 #   chessd_trusted_proxies="<address nginx connects from>"
+# and, for password recovery by email, once the mail jail relays for this one:
+#   chessd_public_url="https://<site>/chess/web-client/"
+#   chessd_smtp_host="<mail jail address>"
+#   chessd_mail_from="Chess <chess@<site>>"
 
 . /etc/rc.subr
 
@@ -43,6 +57,12 @@ load_rc_config "$name"
 : ${chessd_dsn:="postgres:///chess?host=/tmp"}
 : ${chessd_jwt_key:="${chessd_home}/jwt.key"}
 : ${chessd_trusted_proxies:=""}
+: ${chessd_public_url:=""}
+: ${chessd_smtp_host:=""}
+: ${chessd_smtp_port:="25"}
+: ${chessd_smtp_user:=""}
+: ${chessd_smtp_password_file:=""}
+: ${chessd_mail_from:=""}
 : ${chessd_flags:=""}
 
 command="${chessd_bin}"
@@ -85,6 +105,19 @@ chessd_start()
     if [ -n "${chessd_trusted_proxies}" ]; then
         set -- "$@" -trusted-proxies "${chessd_trusted_proxies}"
     fi
+    # Password recovery by email: relay, sender, and the client address the
+    # link opens. The server refuses a relay without the other two.
+    if [ -n "${chessd_smtp_host}" ]; then
+        set -- "$@" -smtp-host "${chessd_smtp_host}" -smtp-port "${chessd_smtp_port}" \
+            -mail-from "${chessd_mail_from}" -public-url "${chessd_public_url}"
+        if [ -n "${chessd_smtp_user}" ]; then
+            set -- "$@" -smtp-user "${chessd_smtp_user}"
+            secret="${chessd_smtp_password_file:-${chessd_home}/smtp.secret}"
+            if [ -f "${secret}" ]; then
+                set -- "$@" -smtp-password-file "${secret}"
+            fi
+        fi
+    fi
 
     echo "Starting ${desc}."
     # -r restarts the server 5 seconds after an unexpected exit (for example

doc/api.md

@@ -116,6 +116,48 @@ Errors: 400 `INVALID_REQUEST` without a password, 401 for a wrong password or
 token, 429 past 5 attempts a minute per IP, 503 `RESOURCE_LIMIT` when password
 hashing is saturated or `STORAGE_UNAVAILABLE` when storage is down.
 
+### Request a Password Reset
+`POST /auth/recover`
+
+Emails a one-time reset link to the account's address. The response is the
+same whether or not the account exists or has an email, so nothing is
+revealed.
+
+**Request:**
+```json
+{"identifier": "alice"}
+```
+
+- `identifier` (string, required): Username or email address
+
+**Response (202):**
+```json
+{"message": "If the account has an email address, a reset link has been sent to it."}
+```
+
+Errors: 429 past 3 requests a minute per IP, 503 `NOT_CONFIGURED` when the
+server has no mail transport (`/health` reports `"mail": "disabled"`), 502
+when the relay refused the message.
+
+### Reset a Password
+`POST /auth/reset`
+
+Sets a new password with the token from the link (`?reset=<token>` on the web
+client) and signs the user in; the token works once, for an hour, and every
+other session of the account ends.
+
+**Request:**
+```json
+{"token": "…", "password": "NewPass123"}
+```
+
+**Response (200):** as login (`token`, `userId`, `username`, `email`,
+`expiresAt`).
+
+Errors: 400 `INVALID_REQUEST` for a weak password or an invalid, used or
+expired token (`"invalid or expired reset link"`), 429 past 10 a minute per
+IP, 503 when storage or password hashing is unavailable.
+
 ## Game Endpoints
 
 ### Health Check
@@ -129,10 +171,14 @@ Returns server and storage status, and the build the server runs.
   "status": "healthy",
   "time": 1699123456,
   "storage": "ok",
+  "mail": "disabled",
   "version": "v0.14.0-3-g1a2b3c4"
 }
 ```
 
+`mail` is `"ok"` when the server can email password-reset links (the web
+client then offers **Forgot password?**), otherwise `"disabled"`.
+
 `version` is `git describe` of the source the binary was built from (`make`
 sets it), or `dev` for a plain `go build`. Compare it after a deployment: a
 client newer than the server gets 404 `NOT_FOUND` for endpoints the server
@@ -556,6 +602,7 @@ Error codes:
 - Registration: 5 requests/minute/IP
 - Login: 10 requests/minute/IP
 - Account deletion: 5 requests/minute/IP
+- Password recovery: 3 requests/minute/IP; reset: 10 requests/minute/IP
 
 Exceeding limit returns 429 status. Behind a reverse proxy the client IP is the
 proxy's `X-Real-IP` header, trusted only from addresses listed in

doc/client.md

@@ -294,6 +294,13 @@ Exit the client.
 chess > exit
 ```
 
+### Long output
+
+`help`, `games`, `pgn`, `state`, `show` and `replay` print one screen at a
+time when their output is taller than the terminal: `-- More (N lines left;
+Enter continues, q quits) --`. The terminal's size comes from the TTY, or in
+the browser from xterm.js; output piped to another program is never paged.
+
 ### Verbose Mode
 
 Append `-v` flag to any command for detailed output:

doc/database.md

@@ -131,9 +131,15 @@ sudo chess-db user list
 su -m chess -c '/home/chess/bin/chess-server db user add -username <name> -dsn "postgres:///chess?host=/tmp"'
 ```
 
-Other `user` subcommands: `delete`, `set-email`, `set-username`, and
+Other `user` subcommands: `delete`, `set-email`, `set-username`, `set-hash`
-`set-hash` (an existing PHC string). CLI-created accounts are identical to
+(an existing PHC string), and `reset-link -url <web client>`, which prints a
-site registrations, and the CLI ignores the registration cap.
+one-time password-reset link (valid an hour) to hand to someone who cannot
+receive the recovery email. CLI-created accounts are identical to site
+registrations, and the CLI ignores the registration cap.
+
+Pending password resets live in `password_resets`: the SHA-256 of the token
+in the emailed link, one per account, deleted when used, expired, or by the
+hourly cleanup. The token itself is never stored.
 
 Sign a user out everywhere (takes effect on their next request):
 

doc/deployment-linux.md

@@ -120,7 +120,7 @@ file is kept next to it with a timestamp).
 | `CHESSD_DSN` | `"host=<socket dir> dbname=chess"` | Database over the socket as the OS account |
 | `CHESSD_JWT_KEY` | `/var/lib/chessd/jwt.key` | Stable signing key |
 | `CHESSD_TRUSTED_PROXIES` | `TRUSTED_PROXIES` | Comma-separated proxy addresses |
-| `CHESSD_FLAGS` | empty | Other server flags, e.g. `-max-users 500 -db-cleanup report` |
+| `CHESSD_FLAGS` | empty | Other server flags, e.g. `-max-users 500 -db-cleanup report`, or password recovery by email: `-smtp-host <relay> -mail-from "Chess <chess@example.com>" -public-url https://example.com/chess/web-client/` (see [deployment.md](deployment.md#password-recovery-by-email); the sandboxed unit can read a password file only under `/var/lib/chessd`) |
 
 Server flags worth knowing: `-max-users` (registration cap, default 100),
 `-anonymous-game-ttl` (default `24h`), `-finished-game-ttl` (default `1h`),

doc/deployment.md

@@ -154,6 +154,10 @@ as `postgres`, list them with `\dt chess.*` and name them as `chess.games`.
 | `chessd_dsn` | `postgres:///chess?host=/tmp` | Database `chess` over the socket as the OS user |
 | `chessd_jwt_key` | `${chessd_home}/jwt.key` | JWT signing key; created (0600) on first start if missing |
 | `chessd_trusted_proxies` | empty | Proxy address(es) whose `X-Real-IP` is trusted |
+| `chessd_public_url` | empty | The web client's public address, which emailed reset links open (`https://<site>/chess/web-client/`) |
+| `chessd_smtp_host`, `chessd_smtp_port` | empty, `25` | SMTP relay for password-reset email; unset leaves recovery off |
+| `chessd_smtp_user`, `chessd_smtp_password_file` | empty, `${chessd_home}/smtp.secret` if present | Relay credentials, when the relay authenticates this host; the file is mode 0600 |
+| `chessd_mail_from` | empty | Sender address, e.g. `Chess <chess@<site>>` |
 | `chessd_flags` | empty | Extra flags, e.g. `-max-users 500 -db-cleanup report` |
 
 The script runs `daemon(8)` as root, which writes the supervisor pidfile
@@ -174,6 +178,11 @@ Server flags:
 | `-anonymous-game-ttl` | | Retention of games without a registered player (default `24h`) |
 | `-finished-game-ttl` | | Memory retention of finished games (default `1h`) |
 | `-db-cleanup` | | Hourly integrity sweep: `off` (default), `report` (log findings), or `delete` ([database.md](database.md#integrity-sweep)) |
+| `-smtp-host`, `-smtp-port` | | SMTP relay for password-reset email (default port 25); recovery is off without a transport |
+| `-smtp-user`, `-smtp-password-file` | | Relay credentials, optional; the file is mode 0600 and only sent over TLS |
+| `-mail-from` | | Sender address of server email |
+| `-mail-dir` | | Development: write email to `.eml` files here instead of a relay |
+| `-public-url` | | The web client's address that emailed links open; required with a transport |
 
 Administrative CLI commands run as `chess` so peer authentication selects the
 right role; root may use `su -m` although the account has no shell:
@@ -186,7 +195,47 @@ jail# su -m chess -c '/home/chess/bin/chess-server db user list -dsn "postgres:/
 (games, with 8-digit ID prefixes), `pgn -gameId <id|prefix> [-ply N]`,
 `verify [-gameId <id|prefix>]` (replays stored games against the rules and
 exits non-zero on a mismatch; run it after an upgrade), and `user add|delete|
-set-password|set-hash|set-email|set-username|list`.
+set-password|set-hash|set-email|set-username|reset-link|list`.
+
+A forgotten password is reset from the jail without mail:
+
+```sh
+jail# su -m chess -c '/home/chess/bin/chess-server db user set-password -username <name> -dsn "postgres:///chess?host=/tmp"'
+```
+
+which prompts for the new password (or takes `-password`), or with a one-time
+link to hand to the person, the same link the recovery email carries:
+
+```sh
+jail# su -m chess -c '/home/chess/bin/chess-server db user reset-link -username <name> -url https://<site>/chess/web-client/ -dsn "postgres:///chess?host=/tmp"'
+```
+
+## Password Recovery by Email
+
+With an SMTP relay the server emails a reset link on request (`POST
+/api/auth/recover`, the **Forgot password?** link in the web client); the link
+opens the client, which sets the new password and signs the person in. The
+link works for an hour and once; using it signs the account out everywhere
+else. Accounts without an email address cannot use it (the CLI commands above
+can).
+
+The relay is a separate jail reached over the internal network. Set in
+`rc.conf`:
+
+```sh
+sysrc chessd_public_url="https://<site>/chess/web-client/"
+sysrc chessd_smtp_host="<mail jail address>"      # chessd_smtp_port, default 25
+sysrc chessd_mail_from="Chess <chess@<site>>"
+# only when the relay authenticates this host:
+sysrc chessd_smtp_user="<user>"
+(umask 077 && echo '<password>' > /home/chess/smtp.secret) && chown chess:chess /home/chess/smtp.secret
+service chessd restart
+```
+
+The server uses STARTTLS when the relay offers it and sends credentials only
+over TLS. `GET /chess/health` reports `"mail": "ok"` once recovery is on. For
+a test without a relay, `-mail-dir <dir>` in `chessd_flags` writes each
+message to a file instead.
 
 ## Host nginx and Web Clients
 

doc/development.md

@@ -38,6 +38,9 @@ go build ./cmd/chess-client-cli
 - `-anonymous-game-ttl`: How long games without a registered player survive after their last activity, in memory and in the database (default: `24h`; `0` keeps them)
 - `-max-users`: Accounts at which public registration closes (default: `100`; `0` = no limit; the CLI is not limited)
 - `-web-api-url`: Browser-visible API origin for the embedded web client, set on its script element as `data-api`; useful when its public origin differs from the listen address
+- `-smtp-host`, `-smtp-port`, `-smtp-user`, `-smtp-password-file`, `-mail-from`: SMTP relay for password-reset email; without a transport, recovery is off
+- `-mail-dir`: Development: write email to `.eml` files in this directory instead of sending
+- `-public-url`: The web client's address that emailed links open (required with a transport)
 
 ### Modes
 ```bash
@@ -223,8 +226,8 @@ go test ./...
 go test -race ./internal/server/storage ./internal/server/service
 
 # Web client end-to-end (Playwright): see test/README.md
-WEB_PORT=9090 test/run-test-server.sh   # terminal 1
+WEB_PORT=9090 MAIL_DIR=/tmp/chess-mail test/run-test-server.sh   # terminal 1
-make test-e2e                           # terminal 2
+CHESS_E2E_MAIL_DIR=/tmp/chess-mail make test-e2e                 # terminal 2
 ```
 
 ## Configuration
@@ -308,7 +311,7 @@ make test-e2e                           # terminal 2
 - JWT tokens don't support refresh (must re-login after expiry)
 - User deletion doesn't cascade to games (games keep player and claim IDs)
 - Games played without a registered player are deleted 24 hours after their last activity
-- No password recovery mechanism
+- Password recovery needs an SMTP relay and an email on the account
 - No email verification for registration
 - Fixed worker pool size for engine calculations
 - No push-based game updates (30-second long-polling is used)

doc/todo.md

@@ -174,13 +174,36 @@ Test gate:
   while replaying, `show` shows the replayed position, and the prompt reads
   `replay <ply>/<plies>`; `live` returns to the game as it was.
 
+Follow-up polish (done): the phone layout is full-width rows under the board
+(`svh` units, so the browser's bars never cover the controls; a replay
+reserves more height than live play), the turn strip says whose move it is in
+two words with the dot showing the side, the sign-in dialog keeps the focus in
+the password field after a wrong password, the brand mark is the site's
+bishop, and the terminal client pages long output (help, games, pgn, state,
+show, replay) one screen at a time, natively and in the browser.
+
 Later for the replay clients:
 
 - [ ] Web: an "Analysis" link on a replay (chess.com-style evaluation needs
   an engine in the browser or a server endpoint; none exists).
-- [ ] Web: a light theme, following the host page's choice.
 - [ ] CLI: `auto` cannot be interrupted before the end of the line.
 
+## Accounts
+
+- [x] Password recovery by email: `POST /api/auth/recover` sends a one-time
+  link (an hour, SHA-256 of the token stored in `password_resets`, schema
+  v4) to the account's address through an SMTP relay (`-smtp-host`, with
+  optional credentials over TLS) or, for development, a directory of `.eml`
+  files (`-mail-dir`); `POST /api/auth/reset` sets the password, ends the
+  account's other sessions and signs the person in; the web client offers
+  **Forgot password?** when `/health` reports `"mail": "ok"` and opens the
+  password form from `?reset=<token>`. `db user reset-link` prints the same
+  link for an administrator; `db user set-password` resets without one.
+- [ ] Deliver from the chess jail through the mail jail (devops): relay
+  address, sender, and `chessd_smtp_*` in `rc.conf` (deployment.md).
+- [ ] Email verification at registration and on `set-email`; today an
+  address is taken as typed, so a typo sends nobody a link.
+
 ## Phase R5 — Curated Archive (later)
 
 - [ ] Schema: game origin (`player`, `curated`), archive metadata (event, site,

go.sum

@@ -3,8 +3,6 @@ github.com/clipperhouse/uax29/v2 v2.7.0/go.mod h1:EFJ2TJMRUaplDxHKj1qAEhCtQPW2tJ
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/gabriel-vasile/mimetype v1.4.15 h1:05iP/CYtZ/w455R/KZM6rZ5ieAdh99UPtd+d3YzLmaI=
-github.com/gabriel-vasile/mimetype v1.4.15/go.mod h1:azpTcoLcDZRNgFou5j+APrqQx9HqVPWa6ijYQIIVswQ=
 github.com/gabriel-vasile/mimetype v1.4.16 h1:5izNFuvA37st1dDRAcA7TtmngBmRgiIPDmTtiEvjx1E=
 github.com/gabriel-vasile/mimetype v1.4.16/go.mod h1:3oFFwxX8kTklZwzIl2aQEDZT0lKY8xH92ST88bAwba4=
 github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
@@ -43,8 +41,6 @@ github.com/mattn/go-runewidth v0.0.31 h1:1oCV4ReTlosDBc6rYRw5cL8S/4y8iv5oRl4SJ5I
 github.com/mattn/go-runewidth v0.0.31/go.mod h1:3qAiGCV4Koz/yuveO58qUefmUTRm8r0IGEXZ9jeHp/8=
 github.com/molecule-man/go-brrr v1.3.0 h1:KEGPkUk9PYFw5+Sv/evCOSU5OmMDXCGFqQ9YjRB7GeU=
 github.com/molecule-man/go-brrr v1.3.0/go.mod h1:7ybW6/7gA3oKY45jOfVNjSJDtrr6ea4tzbsTkjmQDC4=
-github.com/philhofer/fwd v1.2.0 h1:e6DnBTl7vGY+Gz322/ASL4Gyp1FspeMvx1RNDoToZuM=
-github.com/philhofer/fwd v1.2.0/go.mod h1:RqIHx9QI14HlwKwm98g9Re5prTQ6LdeRQn+gXJFxsJM=
 github.com/philhofer/fwd v1.2.1 h1:UtpS73q8bFgy/yH3gCq8LSNvj5gv/FowNOiWZa7uKwQ=
 github.com/philhofer/fwd v1.2.1/go.mod h1:RqIHx9QI14HlwKwm98g9Re5prTQ6LdeRQn+gXJFxsJM=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -58,8 +54,6 @@ github.com/tinylib/msgp v1.6.5 h1:iAH6XTP7BpzErjBZlujJQXxA+GmRi2YWs6M4KdLtNbE=
 github.com/tinylib/msgp v1.6.5/go.mod h1:RSp0LW9oSxFut3KzESt5Voq4GVWyS+PSulT77roAqEA=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
-github.com/valyala/fasthttp v1.75.0 h1:W3xrvNJHG60j2ZCjxpP8kkB+oPG8kh9/g1n4+3xUwNA=
-github.com/valyala/fasthttp v1.75.0/go.mod h1:JiVkPRZU124PuPsreV/s9dZRgG2lRK7wNEikdQ0Rk4s=
 github.com/valyala/fasthttp v1.76.0 h1:QitrT4foDQuqvUnr/hzmQUDbYzV12Zz4vkLOlipU4Cw=
 github.com/valyala/fasthttp v1.76.0/go.mod h1:m8oTPC8riDDky07invpl+Gz3RixnAN5BbwyUuVB5H2o=
 golang.org/x/crypto v0.58.0 h1:COkYLr4k7nDI4r6QtMML2AfzeIswWHAJthLS6K/M/54=

internal/client/api/client.go

@@ -107,7 +107,7 @@ func (c *Client) doRequest(method, path string, body any, result any) error {
 	if resp.StatusCode >= 400 {
 		statusColor = display.Red
 	}
-	fmt.Printf("%s[%d %s]%s\n", statusColor, resp.StatusCode, http.StatusText(resp.StatusCode), display.Reset)
+	display.Printf("%s[%d %s]%s\n", statusColor, resp.StatusCode, http.StatusText(resp.StatusCode), display.Reset)
 
 	// Display response body if verbose
 	if c.Verbose && len(respBody) > 0 {

internal/client/command/auth.go

@@ -81,8 +81,8 @@ func registerHandler(s *session.Session, args []string) error {
 	c.SetToken(resp.Token)
 
 	display.Println(display.Green, "Registered successfully")
-	fmt.Printf("User ID: %s\n", resp.UserID)
+	display.Printf("User ID: %s\n", resp.UserID)
-	fmt.Printf("Username: %s\n", resp.Username)
+	display.Printf("Username: %s\n", resp.Username)
 
 	return nil
 }
@@ -111,8 +111,8 @@ func loginHandler(s *session.Session, args []string) error {
 	c.SetToken(resp.Token)
 
 	display.Println(display.Green, "Logged in successfully")
-	fmt.Printf("User ID: %s\n", resp.UserID)
+	display.Printf("User ID: %s\n", resp.UserID)
-	fmt.Printf("Username: %s\n", resp.Username)
+	display.Printf("Username: %s\n", resp.Username)
 
 	return nil
 }
@@ -151,14 +151,14 @@ func whoamiHandler(s *session.Session, args []string) error {
 	}
 
 	display.Println(display.Cyan, "Current User:")
-	fmt.Printf("  User ID:  %s\n", user.UserID)
+	display.Printf("  User ID:  %s\n", user.UserID)
-	fmt.Printf("  Username: %s\n", user.Username)
+	display.Printf("  Username: %s\n", user.Username)
 	if user.Email != "" {
-		fmt.Printf("  Email:    %s\n", user.Email)
+		display.Printf("  Email:    %s\n", user.Email)
 	}
-	fmt.Printf("  Created:  %s\n", user.CreatedAt.Format("2006-01-02 15:04:05"))
+	display.Printf("  Created:  %s\n", user.CreatedAt.Format("2006-01-02 15:04:05"))
 	if user.LastLogin != nil {
-		fmt.Printf("  Last Login: %s\n", user.LastLogin.Format("2006-01-02 15:04:05"))
+		display.Printf("  Last Login: %s\n", user.LastLogin.Format("2006-01-02 15:04:05"))
 	}
 
 	return nil
@@ -172,7 +172,7 @@ func setUserHandler(s *session.Session, args []string) error {
 	userID := args[0]
 	s.SetCurrentUser(userID)
 	display.Println(display.Cyan, "User ID set to: %s", userID)
-	fmt.Println("Note: This doesn't authenticate, just sets the ID for display")
+	display.Line("Note: This doesn't authenticate, just sets the ID for display")
 
 	return nil
 }

internal/client/command/debug.go

@@ -44,12 +44,12 @@ func healthHandler(s *session.Session, args []string) error {
 	}
 
 	display.Println(display.Cyan, "Server Health:")
-	fmt.Printf("  Status:  %s\n", resp.Status)
+	display.Printf("  Status:  %s\n", resp.Status)
 	// Convert Unix timestamp to readable time
 	t := time.Unix(resp.Time, 0)
-	fmt.Printf("  Time:    %s\n", t.Format("2006-01-02 15:04:05"))
+	display.Printf("  Time:    %s\n", t.Format("2006-01-02 15:04:05"))
 	if resp.Storage != "" {
-		fmt.Printf("  Storage: %s\n", resp.Storage)
+		display.Printf("  Storage: %s\n", resp.Storage)
 	}
 
 	return nil
@@ -57,7 +57,7 @@ func healthHandler(s *session.Session, args []string) error {
 
 func urlHandler(s *session.Session, args []string) error {
 	if len(args) == 0 {
-		fmt.Printf("Current API URL: %s\n", s.GetAPIBaseURL())
+		display.Printf("Current API URL: %s\n", s.GetAPIBaseURL())
 		return nil
 	}
 

internal/client/command/game.go

@@ -59,6 +59,7 @@ func (r *Registry) registerGameCommands() {
 		Description: "Show board and game state",
 		Usage:       "show",
 		Handler:     showBoardHandler,
+		Paged:       true,
 	})
 
 	r.Register(&Command{
@@ -67,6 +68,7 @@ func (r *Registry) registerGameCommands() {
 		Description: "Show raw game JSON",
 		Usage:       "state",
 		Handler:     gameStateHandler,
+		Paged:       true,
 	})
 
 	r.Register(&Command{
@@ -99,6 +101,7 @@ func (r *Registry) registerGameCommands() {
 		Description: "List your stored games, newest first (login required)",
 		Usage:       "games [more]",
 		Handler:     gamesHandler,
+		Paged:       true,
 	})
 
 	r.Register(&Command{
@@ -107,6 +110,7 @@ func (r *Registry) registerGameCommands() {
 		Description: "Print or save a stored game as PGN",
 		Usage:       "pgn [gameId] [ply] [save <path>]  (default: current or replayed game)",
 		Handler:     pgnHandler,
+		Paged:       true,
 	})
 
 	r.Register(&Command{
@@ -259,8 +263,8 @@ func joinGameHandler(s *session.Session, args []string) error {
 		}
 	}
 
-	fmt.Printf("%sJoined game: %s%s\n", display.Green, gameID, display.Reset)
+	display.Printf("%sJoined game: %s%s\n", display.Green, gameID, display.Reset)
-	fmt.Printf("Turn: %s | State: %s | Moves: %d\n", resp.Turn, resp.State, len(resp.Moves))
+	display.Printf("Turn: %s | State: %s | Moves: %d\n", resp.Turn, resp.State, len(resp.Moves))
 
 	return nil
 }
@@ -368,9 +372,9 @@ func computerMoveHandler(s *session.Session, args []string) error {
 	if final.LastMove != nil && len(final.Moves) > baselineMoves {
 		display.Print(display.Magenta, "Computer played: %s", final.LastMove.Move)
 		if final.LastMove.Depth > 0 {
-			fmt.Printf(" (depth %d, score %d)", final.LastMove.Depth, final.LastMove.Score)
+			display.Printf(" (depth %d, score %d)", final.LastMove.Depth, final.LastMove.Score)
 		}
-		fmt.Println()
+		display.Line()
 	}
 
 	printOutcome(final)
@@ -546,28 +550,28 @@ func showBoardHandler(s *session.Session, args []string) error {
 	s.SetGameState(game)
 
 	// Display board with colors
-	fmt.Println()
+	display.Line()
 	display.RenderBoard(board.Board)
 
 	// Display game info
-	fmt.Printf("\nFEN: %s\n", game.FEN)
+	display.Printf("\nFEN: %s\n", game.FEN)
-	fmt.Printf("Turn: %s | State: %s | Moves: %d\n",
+	display.Printf("Turn: %s | State: %s | Moves: %d\n",
 		display.ColorForTurn(game.Turn), game.State, len(game.Moves))
 
 	// Display move history
 	if len(game.Moves) > 0 {
-		fmt.Printf("\nHistory: ")
+		display.Printf("\nHistory: ")
 		for i, move := range game.Moves {
 			if i > 0 {
-				fmt.Print(" ")
+				display.Write(" ")
 			}
 			if i%2 == 0 {
-				fmt.Printf("%d.%s", (i/2)+1, move)
+				display.Printf("%d.%s", (i/2)+1, move)
 			} else {
-				fmt.Printf(" %s", move)
+				display.Printf(" %s", move)
 			}
 		}
-		fmt.Println()
+		display.Line()
 	}
 
 	// Display last move info
@@ -576,11 +580,11 @@ func showBoardHandler(s *session.Session, args []string) error {
 		if game.LastMove.PlayerColor == "b" {
 			color = "Black"
 		}
-		fmt.Printf("Last move: %s by %s", game.LastMove.Move, color)
+		display.Printf("Last move: %s by %s", game.LastMove.Move, color)
 		if game.LastMove.Depth > 0 {
-			fmt.Printf(" (depth %d, score %d)", game.LastMove.Depth, game.LastMove.Score)
+			display.Printf(" (depth %d, score %d)", game.LastMove.Depth, game.LastMove.Score)
 		}
-		fmt.Println()
+		display.Line()
 	}
 	printOutcome(game)
 	printConcession(game)
@@ -630,7 +634,7 @@ func deleteGameHandler(s *session.Session, args []string) error {
 		s.SetLastMoveCount(0)
 	}
 
-	fmt.Printf("%sLive game unloaded (history retained): %s%s\n", display.Green, gameID, display.Reset)
+	display.Printf("%sLive game unloaded (history retained): %s%s\n", display.Green, gameID, display.Reset)
 	return nil
 }
 
@@ -661,7 +665,7 @@ func pollHandler(s *session.Session, args []string) error {
 	case len(resp.Moves) > moveCount:
 		display.Println(display.Green, "Game updated! New moves detected")
 		if resp.LastMove != nil {
-			fmt.Printf("Last move: %s\n", resp.LastMove.Move)
+			display.Printf("Last move: %s\n", resp.LastMove.Move)
 		}
 	case len(resp.Moves) < moveCount:
 		display.Println(display.Green, "Game updated: %d move(s) taken back", moveCount-len(resp.Moves))
@@ -701,9 +705,9 @@ func gamesHandler(s *session.Session, args []string) error {
 		return nil
 	}
 
-	fmt.Printf("\n%3s  %-36s  %-20s  %-20s  %-7s  %5s  %s\n", "#", "Game ID", "White", "Black", "Result", "Plies", "Started (UTC)")
+	display.Printf("\n%3s  %-36s  %-20s  %-20s  %-7s  %5s  %s\n", "#", "Game ID", "White", "Black", "Result", "Plies", "Started (UTC)")
 	for i, g := range resp.Games {
-		fmt.Printf("%3d  %-36s  %-20s  %-20s  %-7s  %5d  %s\n", i+1, g.GameID,
+		display.Printf("%3d  %-36s  %-20s  %-20s  %-7s  %5d  %s\n", i+1, g.GameID,
 			playerLabel(g.Players.White), playerLabel(g.Players.Black), g.PGNResult, g.MoveCount,
 			g.StartTimeUTC.UTC().Format("2006-01-02 15:04"))
 	}
@@ -761,7 +765,7 @@ func pgnHandler(s *session.Session, args []string) error {
 		display.Println(display.Green, "Saved PGN of %s to %s", describePGNTarget(gameID, ply), path)
 		return nil
 	}
-	fmt.Println()
+	display.Line()
-	fmt.Print(text)
+	display.Write(text)
 	return nil
 }

internal/client/command/pass_native.go

@@ -3,15 +3,15 @@
 package command
 
 import (
-	"fmt"
+	"github.com/lixenwraith/chess/internal/client/display"
 
 	"golang.org/x/term"
 )
 
 func readPassword(prompt string) (string, error) {
-	fmt.Print(prompt)
+	display.Write(prompt)
 	bytePassword, err := term.ReadPassword(0) // 0 is stdin
-	fmt.Println()
+	display.Line()
 	if err != nil {
 		return "", err
 	}

internal/client/command/registry.go

@@ -1,6 +1,7 @@
 package command
 
 import (
+	"bytes"
 	"fmt"
 	"strings"
 
@@ -16,6 +17,9 @@ type Command struct {
 	Description string
 	Usage       string
 	Handler     func(*session.Session, []string) error
+	// Paged commands print at length and read nothing: their output is
+	// shown one screen at a time (display.Page).
+	Paged bool
 }
 
 type Registry struct {
@@ -43,6 +47,7 @@ func NewRegistry(s *session.Session) *Registry {
 		Description: "Show available commands",
 		Usage:       "help [command]",
 		Handler:     r.helpHandler,
+		Paged:       true,
 	})
 
 	// Exit command (handled in main loop, but registered for help display)
@@ -89,6 +94,18 @@ func (r *Registry) Execute(input string) {
 		cl.SetVerbose(r.session.IsVerbose())
 	}
 
+	if cmd.Paged && r.session.ReadLine != nil {
+		var buf bytes.Buffer
+		previous := display.Out
+		display.Out = &buf
+		err := cmd.Handler(r.session, args)
+		display.Out = previous
+		display.Page(buf.String(), r.session.ReadLine)
+		if err != nil {
+			display.Println(display.Red, "Error: %s", err.Error())
+		}
+		return
+	}
 	if err := cmd.Handler(r.session, args); err != nil {
 		display.Println(display.Red, "Error: %s", err.Error())
 	}
@@ -101,13 +118,13 @@ func (r *Registry) helpHandler(s *session.Session, args []string) error {
 		if !exists {
 			return fmt.Errorf("unknown command: %s", args[0])
 		}
-		fmt.Println()
+		display.Line()
 		display.Print(display.Cyan, cmd.Name)
 		display.Println(display.Reset, " - %s", cmd.Description)
 		if cmd.ShortName != "" {
 			display.Println(display.Cyan, "Short form: %s", cmd.ShortName)
 		}
-		fmt.Printf("Usage: %s\n", cmd.Usage)
+		display.Printf("Usage: %s\n", cmd.Usage)
 		return nil
 	}
 
@@ -173,10 +190,10 @@ func (r *Registry) helpHandler(s *session.Session, args []string) error {
 				if info.shortName != "" {
 					shortPart = fmt.Sprintf("[%s%s%s] ", display.Cyan, info.shortName, display.Reset)
 				}
-				fmt.Printf("  %s%-10s %s\n", shortPart, cmd.Name, cmd.Description)
+				display.Printf("  %s%-10s %s\n", shortPart, cmd.Name, cmd.Description)
 			}
 		}
-		fmt.Println()
+		display.Line()
 	}
 
 	printCommandGroup("Game Commands", gameCommands)
@@ -185,7 +202,8 @@ func (r *Registry) helpHandler(s *session.Session, args []string) error {
 	printCommandGroup("Utility Commands", utilCommands)
 
 	display.Println(display.Reset, "Type 'help <command>' for detailed usage")
-	display.Println(display.Reset, "Add '-v' to any command for verbose output\n")
+	display.Println(display.Reset, "Add '-v' to any command for verbose output")
+	display.Println(display.Reset, "Long output pauses after each screen: Enter continues, q stops\n")
 	return nil
 }
 

internal/client/command/replay.go

@@ -22,6 +22,7 @@ func (r *Registry) registerReplayCommands() {
 		Description: "Step through a stored game",
 		Usage:       "replay <gameId|index>  (index from the last 'games' listing)",
 		Handler:     replayHandler,
+		Paged:       true,
 	})
 	r.Register(&Command{
 		Name:        "next",
@@ -122,7 +123,7 @@ func replayHandler(s *session.Session, args []string) error {
 
 	white, black := s.Replay.Players()
 	display.Println(display.Cyan, "\nReplaying %s", history.GameID)
-	fmt.Printf("%s vs %s  ·  %s  ·  %d plies  ·  started %s\n",
+	display.Printf("%s vs %s  ·  %s  ·  %d plies  ·  started %s\n",
 		display.C(display.Blue, white), display.C(display.Red, black), s.Replay.Result(), s.Replay.Len(),
 		history.StartTimeUTC.UTC().Format("2006-01-02 15:04"))
 	if c := history.Concession; c != nil {
@@ -135,8 +136,8 @@ func replayHandler(s *session.Session, args []string) error {
 		}
 		display.Println(display.Yellow, "%s at ply %d; play continued.", what, c.Ply)
 	}
-	fmt.Println()
+	display.Line()
-	fmt.Println(s.Replay.Movetext(80))
+	display.Line(s.Replay.Movetext(80))
 	display.Println(display.Reset, "\nnext, prev, first, last, goto <ply>, auto [ms], fen, pgn [save <path>], live")
 	return showReplayPosition(s)
 }
@@ -217,7 +218,7 @@ func fenHandler(s *session.Session, args []string) error {
 	if s.Replay == nil {
 		return errNotReplaying
 	}
-	fmt.Println(s.Replay.FEN())
+	display.Line(s.Replay.FEN())
 	return nil
 }
 
@@ -241,13 +242,13 @@ func showReplayPosition(s *session.Session) error {
 	if err != nil {
 		return fmt.Errorf("stored position cannot be shown: %w", err)
 	}
-	fmt.Println()
+	display.Line()
 	display.RenderBoard(board)
 	label := r.Label(r.Ply)
 	if r.Ply == 0 {
 		label = "initial position"
 	}
-	fmt.Printf("\nPly %d/%d  %s\n", r.Ply, r.Len(), display.C(display.Cyan, label))
+	display.Printf("\nPly %d/%d  %s\n", r.Ply, r.Len(), display.C(display.Cyan, label))
 	if r.AtEnd() && r.History.Result != "" {
 		display.Println(display.Green, "Result: %s", r.Result())
 	}

internal/client/command/save_wasm.go

@@ -2,11 +2,15 @@
 
 package command
 
-import "fmt"
+import (
+	"fmt"
+
+	"github.com/lixenwraith/chess/internal/client/display"
+)
 
 // savePGN has no file system in the browser: the PGN is printed instead,
 // to be copied from the terminal.
 func savePGN(path, text string) error {
-	fmt.Print(text)
+	display.Write(text)
 	return fmt.Errorf("files cannot be saved from the browser; the PGN is printed above")
 }

internal/client/display/board.go

@@ -40,7 +40,7 @@ func RenderBoard(asciiBoard string) {
 				Print(Reset, "%c", char)
 			}
 		}
-		fmt.Println()
+		fmt.Fprintln(Out)
 	}
 }
 

internal/client/display/colors.go

@@ -24,12 +24,12 @@ func C(color, text string) string {
 
 // Print outputs colored text immediately
 func Print(color, format string, args ...any) {
-	fmt.Printf(C(color, format), args...)
+	fmt.Fprintf(Out, C(color, format), args...)
 }
 
 // Println outputs colored text with newline
 func Println(color, format string, args ...any) {
-	fmt.Println(C(color, fmt.Sprintf(format, args...)))
+	fmt.Fprintln(Out, C(color, fmt.Sprintf(format, args...)))
 }
 
 // Build creates a multi-colored string

internal/client/display/format.go

@@ -12,5 +12,5 @@ func PrettyPrintJSON(v any) {
 		Print(Red, "Error formatting JSON: %s\n", err.Error())
 		return
 	}
-	fmt.Println(string(data))
+	fmt.Fprintln(Out, string(data))
 }

internal/client/display/output.go

@@ -0,0 +1,79 @@
+package display
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"regexp"
+	"strings"
+	"unicode/utf8"
+)
+
+// Out receives everything the client prints. A paged command runs with Out
+// swapped for a buffer, which Page then shows one screen at a time.
+var Out io.Writer = os.Stdout
+
+// Printf, Line and Write are fmt.Printf, fmt.Println and fmt.Print to Out.
+func Printf(format string, args ...any) { fmt.Fprintf(Out, format, args...) }
+func Line(args ...any)                  { fmt.Fprintln(Out, args...) }
+func Write(args ...any)                 { fmt.Fprint(Out, args...) }
+
+var ansiPattern = regexp.MustCompile("\x1b\\[[0-9;?]*[ -/]*[@-~]")
+
+// TermSize returns the terminal's rows and columns, or zeros when the output
+// is not a terminal (then nothing is paged). Platform files set it.
+var TermSize = func() (rows, cols int) { return 0, 0 }
+
+// Page prints text to Out one screen at a time. After each full screen it
+// asks to continue; readLine supplies the answer (an empty line continues,
+// "q" stops). Without a terminal, or when the text fits, it prints at once.
+func Page(text string, readLine func() (string, bool)) {
+	rows, cols := TermSize()
+	lines := strings.Split(strings.TrimRight(text, "\n"), "\n")
+	if rows < 4 || readLine == nil || visualRows(lines, cols) <= rows-1 {
+		if text != "" {
+			fmt.Fprint(Out, strings.TrimRight(text, "\n")+"\n")
+		}
+		return
+	}
+	pageRows := rows - 1 // one line for the prompt
+	used, i := 0, 0
+	for i < len(lines) {
+		need := wrappedRows(lines[i], cols)
+		if used > 0 && used+need > pageRows {
+			remaining := len(lines) - i
+			fmt.Fprintf(Out, "%s-- More (%d lines left; Enter continues, q quits) --%s", Yellow, remaining, Reset)
+			answer, ok := readLine()
+			// Clear the prompt and the echoed answer line.
+			fmt.Fprint(Out, "\r\x1b[2K\x1b[1A\r\x1b[2K")
+			if !ok || strings.HasPrefix(strings.ToLower(strings.TrimSpace(answer)), "q") {
+				return
+			}
+			used = 0
+			continue
+		}
+		fmt.Fprintln(Out, lines[i])
+		used += need
+		i++
+	}
+}
+
+func visualRows(lines []string, cols int) int {
+	total := 0
+	for _, line := range lines {
+		total += wrappedRows(line, cols)
+	}
+	return total
+}
+
+// wrappedRows is how many terminal rows a line takes, ignoring colour codes.
+func wrappedRows(line string, cols int) int {
+	if cols <= 0 {
+		return 1
+	}
+	width := utf8.RuneCountInString(ansiPattern.ReplaceAllString(line, ""))
+	if width == 0 {
+		return 1
+	}
+	return (width + cols - 1) / cols
+}

internal/client/display/output_test.go

@@ -0,0 +1,58 @@
+package display
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestPagePrintsScreensAndStopsOnQ(t *testing.T) {
+	var buf bytes.Buffer
+	prevOut, prevSize := Out, TermSize
+	Out = &buf
+	TermSize = func() (int, int) { return 5, 80 } // 4 lines a page
+	defer func() { Out, TermSize = prevOut, prevSize }()
+
+	var lines []string
+	for i := 1; i <= 10; i++ {
+		lines = append(lines, "line "+string(rune('0'+i%10)))
+	}
+	answers := []string{"", "q"}
+	reads := 0
+	readLine := func() (string, bool) {
+		if reads >= len(answers) {
+			return "", false
+		}
+		reads++
+		return answers[reads-1], true
+	}
+	Page(strings.Join(lines, "\n")+"\n", readLine)
+	out := buf.String()
+	if reads != 2 {
+		t.Errorf("prompted %d times, want 2", reads)
+	}
+	if !strings.Contains(out, "line 1\nline 2\nline 3\nline 4\n") || !strings.Contains(out, "More (6 lines left") {
+		t.Errorf("first page = %q", out)
+	}
+	if !strings.Contains(out, "line 5\nline 6\nline 7\nline 8\n") || strings.Contains(out, "line 9") {
+		t.Errorf("second page / stop = %q", out)
+	}
+
+	// Fits on one screen: no prompt. A wrapped long line counts as two rows.
+	buf.Reset()
+	reads = 0
+	Page("a\nb\n", readLine)
+	if buf.String() != "a\nb\n" || reads != 0 {
+		t.Errorf("short text = %q, prompts %d", buf.String(), reads)
+	}
+	if wrappedRows(Red+strings.Repeat("x", 100)+Reset, 80) != 2 || wrappedRows("", 80) != 1 {
+		t.Error("wrapped rows")
+	}
+	// No terminal: everything at once.
+	TermSize = func() (int, int) { return 0, 0 }
+	buf.Reset()
+	Page(strings.Join(lines, "\n"), readLine)
+	if strings.Count(buf.String(), "\n") != 10 || reads != 0 {
+		t.Errorf("unpaged = %q", buf.String())
+	}
+}

internal/client/display/termsize_native.go

@@ -0,0 +1,23 @@
+//go:build !js && !wasm
+
+package display
+
+import (
+	"os"
+
+	"golang.org/x/term"
+)
+
+func init() {
+	TermSize = func() (rows, cols int) {
+		fd := int(os.Stdout.Fd())
+		if !term.IsTerminal(fd) {
+			return 0, 0
+		}
+		cols, rows, err := term.GetSize(fd)
+		if err != nil {
+			return 0, 0
+		}
+		return rows, cols
+	}
+}

internal/client/display/termsize_wasm.go

@@ -0,0 +1,21 @@
+//go:build js && wasm
+
+package display
+
+import "syscall/js"
+
+// The page's terminal wrapper (terminal.js) publishes xterm's size as
+// globalThis.chessTerminal.rows and .cols.
+func init() {
+	TermSize = func() (rows, cols int) {
+		t := js.Global().Get("chessTerminal")
+		if t.IsUndefined() || t.IsNull() {
+			return 24, 80
+		}
+		rows, cols = t.Get("rows").Int(), t.Get("cols").Int()
+		if rows <= 0 || cols <= 0 {
+			return 24, 80
+		}
+		return rows, cols
+	}
+}

internal/client/session/session.go

@@ -18,8 +18,11 @@ type Session struct {
 	Client        *api.Client
 	// Replay is the stored game being stepped through, nil while live. The
 	// live game, user, and poll state above are untouched by a replay.
-	Replay  *replay.State
+	Replay *replay.State
-	Verbose bool
+	// ReadLine reads the next input line (false at end of input); the pager
+	// uses it to wait between screens.
+	ReadLine func() (string, bool)
+	Verbose  bool
 	// Game state for prompt
 	CurrentGameState *api.GameResponse
 	PlayerColor      string // "w", "b", or ""

internal/server/core/error.go

@@ -16,4 +16,5 @@ const (
 	ErrConflict           = "GAME_CONFLICT"
 	ErrStorageUnavailable = "STORAGE_UNAVAILABLE"
 	ErrRouteNotFound      = "NOT_FOUND"
+	ErrNotConfigured      = "NOT_CONFIGURED"
 )

internal/server/http/auth.go

@@ -35,6 +35,17 @@ type DeleteAccountRequest struct {
 	Password string `json:"password" validate:"required"`
 }
 
+// RecoverRequest asks for a password-reset email.
+type RecoverRequest struct {
+	Identifier string `json:"identifier" validate:"required"` // username or email
+}
+
+// ResetPasswordRequest sets a new password with the token from the email.
+type ResetPasswordRequest struct {
+	Token    string `json:"token" validate:"required"`
+	Password string `json:"password" validate:"required"`
+}
+
 // AuthResponse contains JWT token and user information
 type AuthResponse struct {
 	Token     string    `json:"token"`
@@ -322,3 +333,104 @@ func (h *HTTPHandler) DeleteAccountHandler(c *fiber.Ctx) error {
 
 	return c.SendStatus(fiber.StatusNoContent)
 }
+
+// RecoverHandler emails a password-reset link. The answer is the same whether
+// or not the account exists or has an email, so nothing is revealed; only a
+// missing transport (503) or a delivery failure (502) is reported.
+func (h *HTTPHandler) RecoverHandler(c *fiber.Ctx) error {
+	var req RecoverRequest
+	if err := c.BodyParser(&req); err != nil || strings.TrimSpace(req.Identifier) == "" {
+		return c.Status(fiber.StatusBadRequest).JSON(core.ErrorResponse{
+			Error:   "invalid request body",
+			Code:    core.ErrInvalidRequest,
+			Details: "identifier (username or email) is required",
+		})
+	}
+	if len(req.Identifier) > 254 {
+		return c.Status(fiber.StatusBadRequest).JSON(core.ErrorResponse{
+			Error: "invalid identifier", Code: core.ErrInvalidRequest,
+		})
+	}
+
+	if err := h.svc.RequestPasswordReset(req.Identifier); err != nil {
+		switch {
+		case errors.Is(err, service.ErrMailDisabled):
+			return c.Status(fiber.StatusServiceUnavailable).JSON(core.ErrorResponse{
+				Error: "password recovery is not available on this server", Code: core.ErrNotConfigured,
+			})
+		case errors.Is(err, service.ErrMailFailed):
+			return c.Status(fiber.StatusBadGateway).JSON(core.ErrorResponse{
+				Error: "the reset email could not be sent; try again later", Code: core.ErrInternalError,
+			})
+		case errors.Is(err, service.ErrStorageDisabled), errors.Is(err, service.ErrStorageUnavailable):
+			return c.Status(fiber.StatusServiceUnavailable).JSON(core.ErrorResponse{
+				Error: "account storage unavailable", Code: core.ErrStorageUnavailable,
+			})
+		default:
+			return c.Status(fiber.StatusInternalServerError).JSON(core.ErrorResponse{
+				Error: "failed to start password recovery", Code: core.ErrInternalError,
+			})
+		}
+	}
+	return c.Status(fiber.StatusAccepted).JSON(fiber.Map{
+		"message": "If the account has an email address, a reset link has been sent to it.",
+	})
+}
+
+// ResetPasswordHandler sets a new password from a reset link and signs the
+// user in, returning a session token like login.
+func (h *HTTPHandler) ResetPasswordHandler(c *fiber.Ctx) error {
+	var req ResetPasswordRequest
+	if err := c.BodyParser(&req); err != nil || req.Token == "" || req.Password == "" {
+		return c.Status(fiber.StatusBadRequest).JSON(core.ErrorResponse{
+			Error:   "invalid request body",
+			Code:    core.ErrInvalidRequest,
+			Details: "token and password are required",
+		})
+	}
+	if err := validatePassword(req.Password); err != nil {
+		return c.Status(fiber.StatusBadRequest).JSON(core.ErrorResponse{
+			Error:   "weak password",
+			Code:    core.ErrInvalidRequest,
+			Details: err.Error(),
+		})
+	}
+
+	user, sessionID, err := h.svc.ResetPassword(req.Token, req.Password)
+	if err != nil {
+		switch {
+		case errors.Is(err, service.ErrResetInvalid):
+			return c.Status(fiber.StatusBadRequest).JSON(core.ErrorResponse{
+				Error:   "invalid or expired reset link",
+				Code:    core.ErrInvalidRequest,
+				Details: "request a new link from the sign-in dialog",
+			})
+		case errors.Is(err, service.ErrAuthBusy):
+			return c.Status(fiber.StatusServiceUnavailable).JSON(core.ErrorResponse{
+				Error: "authentication temporarily unavailable", Code: core.ErrResourceLimit,
+			})
+		case errors.Is(err, service.ErrStorageDisabled), errors.Is(err, service.ErrStorageUnavailable):
+			return c.Status(fiber.StatusServiceUnavailable).JSON(core.ErrorResponse{
+				Error: "account storage unavailable", Code: core.ErrStorageUnavailable,
+			})
+		default:
+			return c.Status(fiber.StatusInternalServerError).JSON(core.ErrorResponse{
+				Error: "failed to reset password", Code: core.ErrInternalError,
+			})
+		}
+	}
+
+	token, err := h.svc.GenerateUserToken(user.UserID, sessionID)
+	if err != nil {
+		return c.Status(fiber.StatusInternalServerError).JSON(core.ErrorResponse{
+			Error: "failed to generate token", Code: core.ErrInternalError,
+		})
+	}
+	return c.JSON(AuthResponse{
+		Token:     token,
+		UserID:    user.UserID,
+		Username:  user.Username,
+		Email:     user.Email,
+		ExpiresAt: time.Now().Add(service.SessionTTL),
+	})
+}

internal/server/http/handler.go

@@ -140,6 +140,33 @@ func NewFiberApp(proc *processor.Processor, svc *service.Service, opts Options)
 		},
 	}), h.LoginHandler)
 
+	// Password recovery: 3 requests a minute per IP, each of which may send
+	// an email; the reset itself is limited like login.
+	auth.Post("/recover", limiter.New(limiter.Config{
+		Max:          3,
+		Expiration:   1 * time.Minute,
+		KeyGenerator: clientIP,
+		LimitReached: func(c *fiber.Ctx) error {
+			return c.Status(fiber.StatusTooManyRequests).JSON(core.ErrorResponse{
+				Error:   "rate limit exceeded",
+				Code:    core.ErrRateLimitExceeded,
+				Details: "3 recovery requests per minute allowed",
+			})
+		},
+	}), h.RecoverHandler)
+	auth.Post("/reset", limiter.New(limiter.Config{
+		Max:          10,
+		Expiration:   1 * time.Minute,
+		KeyGenerator: clientIP,
+		LimitReached: func(c *fiber.Ctx) error {
+			return c.Status(fiber.StatusTooManyRequests).JSON(core.ErrorResponse{
+				Error:   "rate limit exceeded",
+				Code:    core.ErrRateLimitExceeded,
+				Details: "10 password resets per minute allowed",
+			})
+		},
+	}), h.ResetPasswordHandler)
+
 	// Create token validator closure
 	validateToken := svc.ValidateToken
 
@@ -263,6 +290,7 @@ func (h *HTTPHandler) Health(c *fiber.Ctx) error {
 		"status":  status,
 		"time":    time.Now().Unix(),
 		"storage": storageHealth,
+		"mail":    h.svc.MailHealth(),
 		"version": h.version,
 	})
 }

internal/server/http/handler_test.go

@@ -89,6 +89,8 @@ func TestAPIRoutes(t *testing.T) {
 		"GET /api/auth/me",
 		"POST /api/auth/logout",
 		"DELETE /api/auth/me",
+		"POST /api/auth/recover",
+		"POST /api/auth/reset",
 		"POST /api/games",
 		"GET /api/games/:gameId",
 		"GET /api/games/:gameId/history",

internal/server/mail/mail.go

@@ -0,0 +1,259 @@
+// Package mail sends the server's few transactional messages, today the
+// password-reset link. A Sender is an SMTP relay (production), a directory
+// of .eml files (development and tests), or nothing, in which case the
+// features that need mail are off.
+package mail
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"crypto/tls"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"net"
+	"net/mail"
+	"net/smtp"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// Message is one plain-text email.
+type Message struct {
+	To      string
+	Subject string
+	Body    string
+}
+
+// Sender delivers messages.
+type Sender interface {
+	Send(ctx context.Context, m Message) error
+	// Describe names the transport for logs, without secrets.
+	Describe() string
+}
+
+// SMTP delivers through a relay. Username and Password are optional: a relay
+// inside the same network usually accepts mail from this host without them.
+// STARTTLS is used when the relay offers it; credentials are only ever sent
+// over TLS (or to localhost), which net/smtp enforces.
+type SMTP struct {
+	Host     string
+	Port     int
+	Username string
+	Password string
+	From     string // "Chess <chess@example.com>" or a bare address
+	// Timeout bounds the whole exchange; 30 seconds when zero.
+	Timeout time.Duration
+}
+
+// Describe names the relay.
+func (s *SMTP) Describe() string {
+	auth := "no authentication"
+	if s.Username != "" {
+		auth = "as " + s.Username
+	}
+	return fmt.Sprintf("smtp %s:%d (%s), from %s", s.Host, s.Port, auth, s.From)
+}
+
+// Send delivers one message through the relay.
+func (s *SMTP) Send(ctx context.Context, m Message) error {
+	from, err := mail.ParseAddress(s.From)
+	if err != nil {
+		return fmt.Errorf("mail from %q: %w", s.From, err)
+	}
+	to, err := mail.ParseAddress(m.To)
+	if err != nil {
+		return fmt.Errorf("mail to %q: %w", m.To, err)
+	}
+	timeout := s.Timeout
+	if timeout <= 0 {
+		timeout = 30 * time.Second
+	}
+	if deadline, ok := ctx.Deadline(); ok {
+		if until := time.Until(deadline); until < timeout {
+			timeout = until
+		}
+	}
+	addr := net.JoinHostPort(s.Host, fmt.Sprint(s.Port))
+	conn, err := (&net.Dialer{Timeout: timeout}).DialContext(ctx, "tcp", addr)
+	if err != nil {
+		return fmt.Errorf("connect to %s: %w", addr, err)
+	}
+	defer conn.Close()
+	if err := conn.SetDeadline(time.Now().Add(timeout)); err != nil {
+		return err
+	}
+
+	client, err := smtp.NewClient(conn, s.Host)
+	if err != nil {
+		return fmt.Errorf("smtp handshake with %s: %w", addr, err)
+	}
+	defer client.Close()
+	if ok, _ := client.Extension("STARTTLS"); ok {
+		if err := client.StartTLS(&tls.Config{ServerName: s.Host, MinVersion: tls.VersionTLS12}); err != nil {
+			return fmt.Errorf("starttls with %s: %w", addr, err)
+		}
+	}
+	if s.Username != "" {
+		if err := client.Auth(smtp.PlainAuth("", s.Username, s.Password, s.Host)); err != nil {
+			return fmt.Errorf("smtp authentication with %s: %w", addr, err)
+		}
+	}
+	if err := client.Mail(from.Address); err != nil {
+		return fmt.Errorf("smtp from: %w", err)
+	}
+	if err := client.Rcpt(to.Address); err != nil {
+		return fmt.Errorf("smtp to: %w", err)
+	}
+	w, err := client.Data()
+	if err != nil {
+		return fmt.Errorf("smtp data: %w", err)
+	}
+	if _, err := w.Write(Format(s.From, m)); err != nil {
+		return fmt.Errorf("smtp write: %w", err)
+	}
+	if err := w.Close(); err != nil {
+		return fmt.Errorf("smtp send: %w", err)
+	}
+	return client.Quit()
+}
+
+// Dir writes each message to a file in a directory instead of sending it,
+// for development and tests. The file holds exactly what SMTP would carry.
+type Dir struct {
+	Path string
+	From string
+}
+
+// Describe names the directory.
+func (d *Dir) Describe() string {
+	return fmt.Sprintf("directory %s, from %s", d.Path, d.From)
+}
+
+// Send writes the message as <unix-nanos>-<random>.eml.
+func (d *Dir) Send(_ context.Context, m Message) error {
+	if _, err := mail.ParseAddress(m.To); err != nil {
+		return fmt.Errorf("mail to %q: %w", m.To, err)
+	}
+	if err := os.MkdirAll(d.Path, 0o700); err != nil {
+		return err
+	}
+	var nonce [4]byte
+	rand.Read(nonce[:])
+	name := fmt.Sprintf("%d-%s.eml", time.Now().UnixNano(), hex.EncodeToString(nonce[:]))
+	return os.WriteFile(filepath.Join(d.Path, name), Format(d.From, m), 0o600)
+}
+
+// Format renders the message as RFC 5322 text with CRLF line ends: headers,
+// a blank line, the UTF-8 body. Header values are kept to one line.
+func Format(from string, m Message) []byte {
+	var nonce [8]byte
+	rand.Read(nonce[:])
+	domain := "localhost"
+	if addr, err := mail.ParseAddress(from); err == nil {
+		if at := strings.LastIndex(addr.Address, "@"); at >= 0 {
+			domain = addr.Address[at+1:]
+		}
+	}
+	var b bytes.Buffer
+	header := func(name, value string) {
+		value = strings.NewReplacer("\r", " ", "\n", " ").Replace(value)
+		fmt.Fprintf(&b, "%s: %s\r\n", name, value)
+	}
+	header("From", from)
+	header("To", m.To)
+	header("Subject", m.Subject)
+	header("Date", time.Now().UTC().Format(time.RFC1123Z))
+	header("Message-ID", fmt.Sprintf("<%d.%s@%s>", time.Now().UnixNano(), hex.EncodeToString(nonce[:]), domain))
+	header("MIME-Version", "1.0")
+	header("Content-Type", "text/plain; charset=utf-8")
+	header("Content-Transfer-Encoding", "8bit")
+	header("Auto-Submitted", "auto-generated")
+	b.WriteString("\r\n")
+	body := strings.ReplaceAll(strings.ReplaceAll(m.Body, "\r\n", "\n"), "\n", "\r\n")
+	b.WriteString(body)
+	if !strings.HasSuffix(body, "\r\n") {
+		b.WriteString("\r\n")
+	}
+	return b.Bytes()
+}
+
+// ErrNoSender is returned by Validate for an empty configuration.
+var ErrNoSender = errors.New("no mail transport configured")
+
+// Config is the server's mail configuration, from its flags. SMTPHost or Dir
+// selects the transport; both empty means no mail.
+type Config struct {
+	SMTPHost         string
+	SMTPPort         int
+	SMTPUser         string
+	SMTPPasswordFile string
+	Dir              string
+	From             string
+}
+
+// Build returns the configured Sender, nil (with ErrNoSender) when nothing is
+// configured, or an error for an inconsistent configuration.
+func (c Config) Build() (Sender, error) {
+	switch {
+	case c.SMTPHost != "" && c.Dir != "":
+		return nil, errors.New("-smtp-host and -mail-dir are exclusive")
+	case c.SMTPHost == "" && c.Dir == "":
+		return nil, ErrNoSender
+	}
+	if c.From == "" {
+		return nil, errors.New("-mail-from is required with a mail transport")
+	}
+	if _, err := mail.ParseAddress(c.From); err != nil {
+		return nil, fmt.Errorf("-mail-from %q: %w", c.From, err)
+	}
+	if c.Dir != "" {
+		if err := os.MkdirAll(c.Dir, 0o700); err != nil {
+			return nil, fmt.Errorf("-mail-dir: %w", err)
+		}
+		return &Dir{Path: c.Dir, From: c.From}, nil
+	}
+	port := c.SMTPPort
+	if port <= 0 {
+		port = 25
+	}
+	s := &SMTP{Host: c.SMTPHost, Port: port, Username: c.SMTPUser, From: c.From}
+	if c.SMTPPasswordFile != "" {
+		secret, err := readSecretFile(c.SMTPPasswordFile)
+		if err != nil {
+			return nil, fmt.Errorf("-smtp-password-file: %w", err)
+		}
+		s.Password = secret
+	}
+	if s.Password != "" && s.Username == "" {
+		return nil, errors.New("-smtp-password-file needs -smtp-user")
+	}
+	return s, nil
+}
+
+// readSecretFile reads a one-line secret from a file that only its owner may
+// read, as the JWT key file is.
+func readSecretFile(path string) (string, error) {
+	info, err := os.Stat(path)
+	if err != nil {
+		return "", err
+	}
+	if !info.Mode().IsRegular() {
+		return "", fmt.Errorf("%s is not a regular file", path)
+	}
+	if info.Mode().Perm()&0o077 != 0 {
+		return "", fmt.Errorf("%s is readable by group or others (mode %04o); use mode 0600", path, info.Mode().Perm())
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return "", err
+	}
+	secret := strings.TrimRight(string(data), "\r\n")
+	if secret == "" {
+		return "", fmt.Errorf("%s is empty", path)
+	}
+	return secret, nil
+}

internal/server/mail/mail_test.go

@@ -0,0 +1,91 @@
+package mail
+
+import (
+	"context"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestFormatIsRFC5322WithCRLF(t *testing.T) {
+	text := string(Format("Chess <chess@example.com>", Message{
+		To: "alice@example.com", Subject: "Reset your\npassword", Body: "line one\nline two",
+	}))
+	head, body, ok := strings.Cut(text, "\r\n\r\n")
+	if !ok {
+		t.Fatalf("no header/body separator in %q", text)
+	}
+	for _, want := range []string{
+		"From: Chess <chess@example.com>\r\n", "To: alice@example.com\r\n",
+		"Subject: Reset your password\r\n", "Content-Type: text/plain; charset=utf-8\r\n", "@example.com>\r\n",
+	} {
+		if !strings.Contains(head+"\r\n", want) {
+			t.Errorf("header %q missing in %q", want, head)
+		}
+	}
+	if body != "line one\r\nline two\r\n" {
+		t.Errorf("body = %q", body)
+	}
+	if strings.Contains(text, "\n\n") || strings.Contains(strings.ReplaceAll(text, "\r\n", ""), "\n") {
+		t.Error("bare LF in message")
+	}
+}
+
+func TestDirWritesOneFilePerMessage(t *testing.T) {
+	dir := filepath.Join(t.TempDir(), "mail")
+	d := &Dir{Path: dir, From: "chess@example.com"}
+	if err := d.Send(context.Background(), Message{To: "bob@example.com", Subject: "s", Body: "b"}); err != nil {
+		t.Fatal(err)
+	}
+	if err := d.Send(context.Background(), Message{To: "not an address", Subject: "s", Body: "b"}); err == nil {
+		t.Error("invalid recipient accepted")
+	}
+	entries, err := os.ReadDir(dir)
+	if err != nil || len(entries) != 1 || !strings.HasSuffix(entries[0].Name(), ".eml") {
+		t.Fatalf("entries = %v, %v", entries, err)
+	}
+	data, _ := os.ReadFile(filepath.Join(dir, entries[0].Name()))
+	if !strings.Contains(string(data), "To: bob@example.com\r\n") {
+		t.Errorf("file = %q", data)
+	}
+}
+
+func TestConfigBuild(t *testing.T) {
+	if _, err := (Config{}).Build(); !errors.Is(err, ErrNoSender) {
+		t.Errorf("empty config: %v", err)
+	}
+	for name, c := range map[string]Config{
+		"both transports": {SMTPHost: "h", Dir: "d", From: "a@b.c"},
+		"no from":         {SMTPHost: "h"},
+		"bad from":        {SMTPHost: "h", From: "nope"},
+		"password no user": {SMTPHost: "h", From: "a@b.c", SMTPPasswordFile: func() string {
+			p := filepath.Join(t.TempDir(), "pw")
+			os.WriteFile(p, []byte("secret\n"), 0o600)
+			return p
+		}()},
+	} {
+		if _, err := c.Build(); err == nil {
+			t.Errorf("%s: accepted", name)
+		}
+	}
+	pw := filepath.Join(t.TempDir(), "pw")
+	os.WriteFile(pw, []byte("secret\n"), 0o644)
+	if _, err := (Config{SMTPHost: "h", From: "a@b.c", SMTPUser: "u", SMTPPasswordFile: pw}).Build(); err == nil {
+		t.Error("world-readable password file accepted")
+	}
+	os.Chmod(pw, 0o600)
+	sender, err := (Config{SMTPHost: "mail.internal", From: "Chess <a@b.c>", SMTPUser: "u", SMTPPasswordFile: pw}).Build()
+	if err != nil {
+		t.Fatal(err)
+	}
+	s, ok := sender.(*SMTP)
+	if !ok || s.Port != 25 || s.Password != "secret" || !strings.Contains(s.Describe(), "as u") ||
+		strings.Contains(s.Describe(), "secret") {
+		t.Errorf("smtp = %+v, %q", s, sender.Describe())
+	}
+	if d, err := (Config{Dir: "x", From: "a@b.c"}).Build(); err != nil || d.(*Dir).Path != "x" {
+		t.Errorf("dir = %v, %v", d, err)
+	}
+}

internal/server/service/reset.go

@@ -0,0 +1,208 @@
+package service
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/sha256"
+	"database/sql"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/lixenwraith/chess/internal/server/mail"
+	"github.com/lixenwraith/chess/internal/server/storage"
+
+	"github.com/google/uuid"
+)
+
+const (
+	// PasswordResetTTL is how long a reset link works.
+	PasswordResetTTL = time.Hour
+	resetTokenBytes  = 32
+	mailSendTimeout  = 20 * time.Second
+)
+
+var (
+	// ErrMailDisabled reports that no mail transport is configured, so
+	// password recovery is off.
+	ErrMailDisabled = errors.New("password recovery is not configured")
+	// ErrMailFailed reports a delivery failure to the relay.
+	ErrMailFailed = errors.New("could not send the email")
+	// ErrResetInvalid reports an unknown, used, or expired reset token.
+	ErrResetInvalid = errors.New("invalid or expired reset link")
+)
+
+// mailer is the configured transport and the client URL reset links open.
+type mailer struct {
+	sender    mail.Sender
+	publicURL *url.URL
+}
+
+// SetMailer configures password recovery: sender delivers the email and
+// publicURL is the web client's address, which the link opens with
+// ?reset=<token>. A nil sender turns recovery off.
+func (s *Service) SetMailer(sender mail.Sender, publicURL string) error {
+	if sender == nil {
+		s.mail = nil
+		return nil
+	}
+	u, err := url.Parse(publicURL)
+	if err != nil || u.Scheme == "" || u.Host == "" {
+		return fmt.Errorf("public URL %q must be absolute (https://host/chess/web-client/)", publicURL)
+	}
+	s.mail = &mailer{sender: sender, publicURL: u}
+	return nil
+}
+
+// MailHealth reports "ok" when password recovery can send mail, otherwise
+// "disabled".
+func (s *Service) MailHealth() string {
+	if s.mail == nil || s.store == nil {
+		return "disabled"
+	}
+	return "ok"
+}
+
+// NewResetToken returns a fresh reset token and the hash stored for it.
+func NewResetToken() (token string, hash []byte, err error) {
+	raw := make([]byte, resetTokenBytes)
+	if _, err := rand.Read(raw); err != nil {
+		return "", nil, err
+	}
+	token = base64.RawURLEncoding.EncodeToString(raw)
+	return token, hashResetToken(token), nil
+}
+
+func hashResetToken(token string) []byte {
+	sum := sha256.Sum256([]byte(token))
+	return sum[:]
+}
+
+// ResetLink is the web client URL that opens the password form for token.
+func ResetLink(publicURL *url.URL, token string) string {
+	u := *publicURL
+	q := u.Query()
+	q.Set("reset", token)
+	u.RawQuery = q.Encode()
+	u.Fragment = ""
+	return u.String()
+}
+
+// RequestPasswordReset emails a reset link to the account named by
+// identifier (username or email) when it has an email address. It reports
+// success for unknown accounts and accounts without an email, so the request
+// reveals nothing about who is registered; the caller sees the same answer.
+func (s *Service) RequestPasswordReset(identifier string) error {
+	if s.store == nil {
+		return ErrStorageDisabled
+	}
+	if s.mail == nil {
+		return ErrMailDisabled
+	}
+	identifier = strings.ToLower(strings.TrimSpace(identifier))
+	var record *storage.UserRecord
+	var err error
+	if strings.Contains(identifier, "@") {
+		record, err = s.store.GetUserByEmail(identifier)
+	} else {
+		record, err = s.store.GetUserByUsername(identifier)
+	}
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			slog.Info("password reset requested for an unknown account")
+			return nil
+		}
+		return fmt.Errorf("%w: look up user: %v", ErrStorageUnavailable, err)
+	}
+	if record.Email == "" {
+		slog.Info("password reset requested for an account without email", "user_id", record.UserID)
+		return nil
+	}
+
+	token, hash, err := NewResetToken()
+	if err != nil {
+		return fmt.Errorf("generate reset token: %w", err)
+	}
+	now := time.Now().UTC()
+	if err := s.store.CreatePasswordReset(storage.PasswordResetRecord{
+		UserID: record.UserID, TokenHash: hash, CreatedAt: now, ExpiresAt: now.Add(PasswordResetTTL),
+	}); err != nil {
+		return fmt.Errorf("%w: store reset: %v", ErrStorageUnavailable, err)
+	}
+
+	link := ResetLink(s.mail.publicURL, token)
+	ctx, cancel := context.WithTimeout(context.Background(), mailSendTimeout)
+	defer cancel()
+	err = s.mail.sender.Send(ctx, mail.Message{
+		To:      record.Email,
+		Subject: "Reset your chess password",
+		Body: fmt.Sprintf(`Hello %s,
+
+Someone asked to reset the password of your chess account at %s.
+If it was you, open this link within the next hour:
+
+  %s
+
+If you did not ask for this, ignore this message: your password stays as
+it is and nobody else can use the link without this email.
+`, record.Username, s.mail.publicURL.Host, link),
+	})
+	if err != nil {
+		slog.Error("password reset email failed", "user_id", record.UserID, "error", err)
+		return ErrMailFailed
+	}
+	slog.Info("password reset email sent", "user_id", record.UserID)
+	return nil
+}
+
+// ResetPassword sets a new password for the account whose pending reset
+// token this is, ends its other sessions, and signs the user in. The token
+// works once and only until its expiry.
+func (s *Service) ResetPassword(token, password string) (*User, string, error) {
+	if s.store == nil {
+		return nil, "", ErrStorageDisabled
+	}
+	if raw, err := base64.RawURLEncoding.DecodeString(token); err != nil || len(raw) != resetTokenBytes {
+		return nil, "", ErrResetInvalid
+	}
+	now := time.Now().UTC()
+	userID, err := s.store.ConsumePasswordReset(hashResetToken(token), now)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, "", ErrResetInvalid
+		}
+		return nil, "", fmt.Errorf("%w: consume reset: %v", ErrStorageUnavailable, err)
+	}
+
+	passwordHash, err := s.hashPassword(password)
+	if err != nil {
+		if errors.Is(err, ErrAuthBusy) {
+			return nil, "", err
+		}
+		return nil, "", fmt.Errorf("failed to hash password: %w", err)
+	}
+	if err := s.store.ResetUserPassword(userID, passwordHash); err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, "", ErrResetInvalid
+		}
+		return nil, "", fmt.Errorf("%w: reset password: %v", ErrStorageUnavailable, err)
+	}
+	record, err := s.store.GetUserByID(userID)
+	if err != nil {
+		return nil, "", fmt.Errorf("%w: look up user: %v", ErrStorageUnavailable, err)
+	}
+	sessionID := uuid.NewString()
+	if err := s.store.CreateSession(storage.SessionRecord{
+		SessionID: sessionID, UserID: userID, CreatedAt: now, ExpiresAt: now.Add(SessionTTL),
+	}); err != nil {
+		return nil, "", fmt.Errorf("%w: create session: %v", ErrStorageUnavailable, err)
+	}
+	slog.Info("password reset completed", "user_id", userID)
+	return &User{
+		UserID: record.UserID, Username: record.Username, Email: record.Email, CreatedAt: record.CreatedAt,
+	}, sessionID, nil
+}

internal/server/service/reset_test.go

@@ -0,0 +1,147 @@
+package service
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/lixenwraith/chess/internal/server/mail"
+	"github.com/lixenwraith/chess/internal/server/storage"
+)
+
+var linkPattern = regexp.MustCompile(`https://example\.test/chess/web-client/\?reset=([A-Za-z0-9_-]{43})`)
+
+func TestPasswordResetFlow(t *testing.T) {
+	svc := newPersistentTestService(t)
+	if svc.MailHealth() != "disabled" {
+		t.Fatal("mail reported before configuration")
+	}
+	if err := svc.RequestPasswordReset("alice"); !errors.Is(err, ErrMailDisabled) {
+		t.Fatalf("recovery without mail: %v", err)
+	}
+	dir := filepath.Join(t.TempDir(), "mail")
+	if err := svc.SetMailer(&mail.Dir{Path: dir, From: "chess@example.test"}, "/chess/"); err == nil {
+		t.Fatal("relative public URL accepted")
+	}
+	if err := svc.SetMailer(&mail.Dir{Path: dir, From: "chess@example.test"}, "https://example.test/chess/web-client/"); err != nil {
+		t.Fatal(err)
+	}
+	if svc.MailHealth() != "ok" {
+		t.Fatal("mail not reported ok")
+	}
+
+	user, sessionID, err := svc.RegisterUser("alice", "Alice@Example.test", "Password1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, _, err := svc.RegisterUser("bob", "", "Password1"); err != nil {
+		t.Fatal(err)
+	}
+
+	// Unknown accounts and accounts without email get the same answer and no mail.
+	for _, id := range []string{"nobody", "nobody@example.test", "bob"} {
+		if err := svc.RequestPasswordReset(id); err != nil {
+			t.Errorf("recover %q: %v", id, err)
+		}
+	}
+	if entries, _ := os.ReadDir(dir); len(entries) != 0 {
+		t.Fatalf("mail sent for unknown accounts: %d files", len(entries))
+	}
+
+	// By email, case-insensitively; then by username, which replaces the link.
+	if err := svc.RequestPasswordReset("ALICE@example.test"); err != nil {
+		t.Fatal(err)
+	}
+	first := lastMailToken(t, dir)
+	if err := svc.RequestPasswordReset("alice"); err != nil {
+		t.Fatal(err)
+	}
+	token := lastMailToken(t, dir)
+	if token == first {
+		t.Fatal("second request reused the token")
+	}
+	if _, _, err := svc.ResetPassword(first, "Password2"); !errors.Is(err, ErrResetInvalid) {
+		t.Errorf("replaced token: %v", err)
+	}
+	for _, bad := range []string{"", "x", strings.Repeat("A", 43), token + "A"} {
+		if _, _, err := svc.ResetPassword(bad, "Password2"); !errors.Is(err, ErrResetInvalid) {
+			t.Errorf("token %q: %v", bad, err)
+		}
+	}
+
+	reset, newSession, err := svc.ResetPassword(token, "Password2")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if reset.UserID != user.UserID || reset.Username != "alice" || newSession == "" || newSession == sessionID {
+		t.Fatalf("reset returned %+v, session %q", reset, newSession)
+	}
+	if _, _, err := svc.ResetPassword(token, "Password3"); !errors.Is(err, ErrResetInvalid) {
+		t.Errorf("token reused: %v", err)
+	}
+	// The old session is gone, the new one and the new password work.
+	if _, _, err := svc.ValidateToken(mustToken(t, svc, user.UserID, sessionID)); err == nil {
+		t.Error("old session still valid")
+	}
+	if _, _, err := svc.ValidateToken(mustToken(t, svc, user.UserID, newSession)); err != nil {
+		t.Errorf("new session invalid: %v", err)
+	}
+	if _, _, err := svc.AuthenticateUser("alice", "Password1"); !errors.Is(err, ErrInvalidCredentials) {
+		t.Errorf("old password: %v", err)
+	}
+	if _, _, err := svc.AuthenticateUser("alice", "Password2"); err != nil {
+		t.Errorf("new password: %v", err)
+	}
+
+	// An expired link is refused and the cleanup removes it.
+	expired, hash, err := NewResetToken()
+	if err != nil {
+		t.Fatal(err)
+	}
+	past := time.Now().UTC().Add(-time.Minute)
+	if err := svc.store.CreatePasswordReset(storage.PasswordResetRecord{
+		UserID: user.UserID, TokenHash: hash, CreatedAt: past.Add(-time.Hour), ExpiresAt: past,
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if _, _, err := svc.ResetPassword(expired, "Password4"); !errors.Is(err, ErrResetInvalid) {
+		t.Errorf("expired token: %v", err)
+	}
+	if deleted, err := svc.store.DeleteExpiredPasswordResets(); err != nil || deleted != 1 {
+		t.Errorf("expired resets deleted = %d, %v", deleted, err)
+	}
+}
+
+func lastMailToken(t *testing.T, dir string) string {
+	t.Helper()
+	entries, err := os.ReadDir(dir)
+	if err != nil || len(entries) == 0 {
+		t.Fatalf("no mail in %s: %v", dir, err)
+	}
+	data, err := os.ReadFile(filepath.Join(dir, entries[len(entries)-1].Name()))
+	if err != nil {
+		t.Fatal(err)
+	}
+	text := string(data)
+	if !strings.Contains(text, "To: alice@example.test\r\n") || !strings.Contains(text, "Subject: Reset your chess password\r\n") {
+		t.Fatalf("mail = %q", text)
+	}
+	m := linkPattern.FindStringSubmatch(text)
+	if m == nil {
+		t.Fatalf("no reset link in %q", text)
+	}
+	return m[1]
+}
+
+func mustToken(t *testing.T, svc *Service, userID, sessionID string) string {
+	t.Helper()
+	token, err := svc.GenerateUserToken(userID, sessionID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return token
+}

internal/server/service/service.go

@@ -41,6 +41,8 @@ type Service struct {
 
 	integrityMode   IntegrityMode
 	integrityCursor string // last game ID the integrity sweep verified; cleanup goroutine only
+
+	mail *mailer // password recovery; nil when no transport is configured
 }
 
 // New creates a service with optional storage. jwtSecret signs session tokens
@@ -193,6 +195,11 @@ func (s *Service) cleanupExpired() {
 		} else if deleted > 0 {
 			slog.Info("cleanup deleted expired sessions", "count", deleted)
 		}
+		if deleted, err := s.store.DeleteExpiredPasswordResets(); err != nil {
+			slog.Error("cleanup failed to delete expired password resets", "error", err)
+		} else if deleted > 0 {
+			slog.Info("cleanup deleted expired password resets", "count", deleted)
+		}
 	}
 	s.cleanupGames(now)
 	s.checkIntegrity(now)

internal/server/storage/reset.go

@@ -0,0 +1,120 @@
+package storage
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"log/slog"
+	"time"
+)
+
+// PasswordResetRecord is a pending password reset: the SHA-256 of the token
+// sent to the account's email, and when it stops working.
+type PasswordResetRecord struct {
+	UserID    string
+	TokenHash []byte
+	CreatedAt time.Time
+	ExpiresAt time.Time
+}
+
+// CreatePasswordReset stores a reset for the user, replacing any pending one,
+// so only the latest link works. It returns sql.ErrNoRows for an unknown
+// user.
+func (s *Store) CreatePasswordReset(record PasswordResetRecord) error {
+	if !validUUID(record.UserID) {
+		return sql.ErrNoRows
+	}
+	if len(record.TokenHash) != 32 {
+		return errors.New("token hash must be 32 bytes")
+	}
+	ctx, cancel := opContext()
+	defer cancel()
+	result, err := s.db.ExecContext(ctx, `INSERT INTO password_resets (user_id, token_hash, created_at, expires_at)
+		SELECT user_id, $2, $3, $4 FROM users WHERE user_id = $1
+		ON CONFLICT (user_id) DO UPDATE SET
+			token_hash = excluded.token_hash,
+			created_at = excluded.created_at,
+			expires_at = excluded.expires_at`,
+		record.UserID, record.TokenHash, record.CreatedAt, record.ExpiresAt)
+	if err != nil {
+		return fmt.Errorf("create password reset: %w", err)
+	}
+	if rows, err := result.RowsAffected(); err != nil {
+		return err
+	} else if rows == 0 {
+		return sql.ErrNoRows
+	}
+	slog.Debug("storage password reset created", "user_id", record.UserID, "expires_at", record.ExpiresAt)
+	return nil
+}
+
+// ConsumePasswordReset deletes the reset matching tokenHash and returns its
+// user, or sql.ErrNoRows when none is pending or it has expired. A token
+// works once.
+func (s *Store) ConsumePasswordReset(tokenHash []byte, now time.Time) (string, error) {
+	if len(tokenHash) != 32 {
+		return "", sql.ErrNoRows
+	}
+	ctx, cancel := opContext()
+	defer cancel()
+	var userID string
+	err := s.db.QueryRowContext(ctx,
+		`DELETE FROM password_resets WHERE token_hash = $1 AND expires_at > $2 RETURNING user_id`,
+		tokenHash, now.UTC()).Scan(&userID)
+	if err != nil {
+		return "", err
+	}
+	return userID, nil
+}
+
+// DeleteExpiredPasswordResets removes resets past their expiry.
+func (s *Store) DeleteExpiredPasswordResets() (int64, error) {
+	ctx, cancel := opContext()
+	defer cancel()
+	result, err := s.db.ExecContext(ctx, `DELETE FROM password_resets WHERE expires_at < $1`, time.Now().UTC())
+	if err != nil {
+		return 0, err
+	}
+	deleted, err := result.RowsAffected()
+	if err == nil && deleted > 0 {
+		slog.Debug("storage expired password resets deleted", "count", deleted)
+	}
+	return deleted, err
+}
+
+// ResetUserPassword sets a new password hash and ends the user's sessions in
+// one transaction: whoever held the old password is signed out everywhere.
+// It returns sql.ErrNoRows for an unknown user.
+func (s *Store) ResetUserPassword(userID, passwordHash string) error {
+	if !validUUID(userID) {
+		return sql.ErrNoRows
+	}
+	ctx, cancel := opContext()
+	defer cancel()
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("failed to begin transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	result, err := tx.ExecContext(ctx, `UPDATE users SET password_hash = $2 WHERE user_id = $1`, userID, passwordHash)
+	if err != nil {
+		return fmt.Errorf("update password: %w", err)
+	}
+	if rows, err := result.RowsAffected(); err != nil {
+		return err
+	} else if rows == 0 {
+		return sql.ErrNoRows
+	}
+	if _, err := tx.ExecContext(ctx, `DELETE FROM sessions WHERE user_id = $1`, userID); err != nil {
+		return fmt.Errorf("end sessions: %w", err)
+	}
+	if _, err := tx.ExecContext(ctx, `DELETE FROM password_resets WHERE user_id = $1`, userID); err != nil {
+		return fmt.Errorf("clear password resets: %w", err)
+	}
+	if err := tx.Commit(); err != nil {
+		return err
+	}
+	slog.Debug("storage password reset", "user_id", userID)
+	return nil
+}

internal/server/storage/schema.go

@@ -81,7 +81,7 @@ type MovePersistence struct {
 // schemaVersion is the newest schema this binary understands. Migrations are
 // applied in order inside one transaction; PostgreSQL DDL is transactional, so
 // a failed upgrade leaves the previous version intact.
-const schemaVersion = 3
+const schemaVersion = 4
 
 // migrations[v-1] upgrades the schema from version v-1 to v. Never edit a
 // released migration; append a new one.
@@ -212,8 +212,23 @@ ALTER TABLE games ADD CONSTRAINT games_concession_check CHECK (
 	OR (concession_ply >= 0 AND concession_time_utc IS NOT NULL AND (
 		(concession_result IN ('white_wins', 'black_wins') AND concession_termination = 'resignation')
 		OR (concession_result = 'draw' AND concession_termination = 'agreement'))));
+`,
+
+	// v4: password recovery. One pending reset per account; the token the
+	// email carries is never stored, only its SHA-256, and it expires after
+	// an hour. Consuming a token deletes the row.
+	`
+CREATE TABLE password_resets (
+	user_id    uuid PRIMARY KEY REFERENCES users (user_id) ON DELETE CASCADE,
+	token_hash bytea NOT NULL,
+	created_at timestamptz NOT NULL DEFAULT now(),
+	expires_at timestamptz NOT NULL,
+	CONSTRAINT password_resets_token_hash_key UNIQUE (token_hash),
+	CONSTRAINT password_resets_token_hash_check CHECK (octet_length(token_hash) = 32)
+);
+CREATE INDEX password_resets_expires_at_idx ON password_resets (expires_at);
 `,
 }
 
 // ownedTables lists every table created by migrations, children first.
-var ownedTables = []string{"moves", "games", "sessions", "users", "schema_version"}
+var ownedTables = []string{"moves", "games", "password_resets", "sessions", "users", "schema_version"}

internal/server/webserver/chess-client-web/app.js

@@ -93,6 +93,7 @@ const games = {
 const ui = {
     healthTimer: null,
     storage: 'unknown',
+    mail: 'unknown',    // "ok" when the server emails password-reset links
     toastTimer: null,
     historyCache: new Map(), // gameId -> {etag, history}
 };
@@ -211,6 +212,22 @@ function describeResult(state, termination) {
     return 'Game over';
 }
 
+// shortResult is the outcome in a few words, for the narrow turn strip.
+function shortResult(state, termination) {
+    const winner = state === 'white wins' ? 'White' : 'Black';
+    switch (termination) {
+        case 'resignation': return `${winner} wins · resigned`;
+        case 'checkmate': return `${winner} wins · mate`;
+        case 'stalemate': return 'Draw · stalemate';
+        case 'insufficient_material': return 'Draw · material';
+        case 'threefold_repetition': return 'Draw · repetition';
+        case 'fifty_move_rule': return 'Draw · 50 moves';
+        case 'agreement': return 'Draw · agreed';
+    }
+    if (state === 'white wins' || state === 'black wins') return `${winner} wins`;
+    return 'Draw';
+}
+
 function terminationLabel(termination) {
     switch (termination) {
         case 'checkmate': return 'Checkmate';
@@ -358,6 +375,11 @@ function setStorageStatus(status) {
     updateLiveTools();
 }
 
+function setMailStatus(status) {
+    ui.mail = status;
+    $('forgot-row').classList.toggle('hidden', status !== 'ok');
+}
+
 function startHealthCheck() {
     const checkHealth = async () => {
         try {
@@ -366,6 +388,7 @@ function startHealthCheck() {
                 const health = await response.json();
                 setServerStatus(health.status === 'healthy' ? 'healthy' : 'degraded');
                 setStorageStatus(health.storage || 'unknown');
+                setMailStatus(health.mail || 'disabled');
             } else {
                 handleApiError('health check', null, response);
                 setStorageStatus('unknown');
@@ -551,7 +574,8 @@ async function deleteAccount() {
 // re-entrancy from the Enter-key handler and stops edits mid-request.
 function setAuthModalBusy(busy) {
     auth.busy = busy;
-    for (const id of ['login-submit-btn', 'register-submit-btn', 'auth-cancel-btn', 'auth-cancel-btn-2']) {
+    for (const id of ['login-submit-btn', 'register-submit-btn', 'auth-cancel-btn', 'auth-cancel-btn-2',
+        'forgot-btn', 'recover-submit-btn', 'recover-back-btn']) {
         $(id).disabled = busy;
     }
     document.querySelectorAll('.auth-tab').forEach(t => t.disabled = busy);
@@ -560,7 +584,7 @@ function setAuthModalBusy(busy) {
 
 function showAuthModal() {
     $('auth-modal-overlay').classList.add('show');
-    $('login-identifier').focus();
+    switchAuthTab('login');
     document.removeEventListener('keydown', handleAuthModalKeydown);
     document.addEventListener('keydown', handleAuthModalKeydown);
 }
@@ -584,50 +608,72 @@ function handleAuthModalKeydown(e) {
         hideAuthModal();
     } else if (e.key === 'Enter') {
         e.preventDefault();
-        if (!$('login-form').classList.contains('hidden')) handleLogin(); else handleRegister();
+        ({ login: handleLogin, register: handleRegister, recover: handleRecover })[activeAuthForm()]();
     }
 }
 
+// The auth modal shows one of three forms: sign in, register, or password
+// recovery (reached from the sign-in form, without a tab).
 function switchAuthTab(tab) {
     document.querySelectorAll('.auth-tab').forEach(t => {
         const active = t.dataset.tab === tab;
         t.classList.toggle('active', active);
         t.setAttribute('aria-selected', active ? 'true' : 'false');
     });
+    document.querySelector('.auth-tabs').classList.toggle('hidden', tab === 'recover');
     $('login-form').classList.toggle('hidden', tab !== 'login');
     $('register-form').classList.toggle('hidden', tab !== 'register');
+    $('recover-form').classList.toggle('hidden', tab !== 'recover');
     clearModalMessage('auth-modal-message');
-    $(tab === 'login' ? 'login-identifier' : 'register-username').focus();
+    $({ login: 'login-identifier', register: 'register-username', recover: 'recover-identifier' }[tab]).focus();
 }
 
-async function submitAuth(path, body, failure) {
+function activeAuthForm() {
+    if (!$('login-form').classList.contains('hidden')) return 'login';
+    if (!$('register-form').classList.contains('hidden')) return 'register';
+    return 'recover';
+}
+
+// Returns the focus to a field after a failed request: the request disabled
+// the fields, which drops the focus to the page, and a retyped password
+// would otherwise go nowhere.
+function refocus(id, select = true) {
+    const el = $(id);
+    if (!el) return;
+    el.focus();
+    if (select && typeof el.select === 'function') el.select();
+}
+
+async function submitAuth(path, body, failure, focusId) {
     setAuthModalBusy(true);
     clearModalMessage('auth-modal-message');
 
+    const fail = message => {
+        setModalMessage('auth-modal-message', message, 'error');
+        setAuthModalBusy(false);
+        refocus(focusId);
+        return null;
+    };
+
     let response;
     try {
         response = await apiJSON('POST', path, body);
     } catch (error) {
-        const errorInfo = handleApiError(path, error);
+        return fail(handleApiError(path, error).statusMessage);
-        setModalMessage('auth-modal-message', errorInfo.statusMessage, 'error');
-        setAuthModalBusy(false);
-        return null;
     }
 
     if (!response.ok) {
         const err = await parseErrorResponse(response);
-        setModalMessage('auth-modal-message', err.details || err.error || failure, 'error');
+        if (response.status === 401) return fail('Wrong username or password');
-        setAuthModalBusy(false);
+        if (response.status === 429) return fail('Too many attempts. Wait a minute and try again.');
-        return null;
+        return fail(err.details || err.error || failure);
     }
 
     try {
         return await response.json();
     } catch (error) {
         console.error(`${path}: response OK but JSON parse failed:`, error);
-        setModalMessage('auth-modal-message', 'Unexpected response from server', 'error');
+        return fail('Unexpected response from server');
-        setAuthModalBusy(false);
-        return null;
     }
 }
 
@@ -637,15 +683,156 @@ async function handleLogin() {
     const password = $('login-password').value;
     if (!identifier || !password) {
         setModalMessage('auth-modal-message', 'Fill in both fields', 'error');
+        refocus(identifier ? 'login-password' : 'login-identifier', false);
         return;
     }
-    const result = await submitAuth('/api/auth/login', { identifier, password }, 'Sign-in failed');
+    const result = await submitAuth('/api/auth/login', { identifier, password }, 'Sign-in failed', 'login-password');
     if (!result) return;
     setSignedIn(result.userId, result.username, result.token);
     setModalMessage('auth-modal-message', `Signed in as ${result.username}`, 'success');
     setTimeout(hideAuthModal, MODAL_SUCCESS_DISPLAY_MS);
 }
 
+// The server's password rule, checked first for a quicker answer.
+function passwordProblem(password) {
+    if (password.length < 8) return 'Password needs at least 8 characters';
+    if (!/[a-zA-Z]/.test(password) || !/[0-9]/.test(password)) return 'Password needs a letter and a number';
+    return '';
+}
+
+// Asks for a reset link. The server answers the same whether or not the
+// account exists, so the message is the same too.
+async function handleRecover() {
+    if (auth.busy) return;
+    const identifier = $('recover-identifier').value.trim();
+    if (!identifier) {
+        setModalMessage('auth-modal-message', 'Enter your username or email', 'error');
+        refocus('recover-identifier', false);
+        return;
+    }
+    setAuthModalBusy(true);
+    clearModalMessage('auth-modal-message');
+    let response;
+    try {
+        response = await apiJSON('POST', '/api/auth/recover', { identifier });
+    } catch (error) {
+        setModalMessage('auth-modal-message', handleApiError('recover', error).statusMessage, 'error');
+        setAuthModalBusy(false);
+        refocus('recover-identifier');
+        return;
+    }
+    setAuthModalBusy(false);
+    if (response.status === 202) {
+        setModalMessage('auth-modal-message', 'If the account has an email address, a reset link is on its way. Check your inbox.', 'success');
+        $('recover-identifier').value = '';
+        $('recover-back-btn').focus();
+        return;
+    }
+    const err = await parseErrorResponse(response);
+    let message = err.error || 'Could not send the link';
+    if (response.status === 429) message = 'Too many requests. Wait a minute and try again.';
+    else if (response.status === 503 && err.code === 'NOT_CONFIGURED') message = 'This server cannot send email; ask its administrator for a reset link.';
+    setModalMessage('auth-modal-message', message, 'error');
+    refocus('recover-identifier');
+}
+
+// --- reset: the link in the recovery email opens the client with ?reset=<token>
+
+const reset = { token: null, busy: false };
+
+function openResetModal(token) {
+    reset.token = token;
+    reset.busy = false;
+    $('reset-password').value = '';
+    $('reset-password-2').value = '';
+    clearModalMessage('reset-modal-message');
+    $('reset-overlay').classList.add('show');
+    document.removeEventListener('keydown', handleResetKeydown);
+    document.addEventListener('keydown', handleResetKeydown);
+    $('reset-password').focus();
+}
+
+function closeResetModal() {
+    if (reset.busy) return;
+    reset.token = null;
+    $('reset-overlay').classList.remove('show');
+    $('reset-password').value = '';
+    $('reset-password-2').value = '';
+    document.removeEventListener('keydown', handleResetKeydown);
+}
+
+function setResetBusy(busy) {
+    reset.busy = busy;
+    for (const id of ['reset-password', 'reset-password-2', 'reset-submit-btn', 'reset-cancel-btn']) {
+        $(id).disabled = busy;
+    }
+}
+
+function handleResetKeydown(e) {
+    if (reset.busy) {
+        if (e.key === 'Enter' || e.key === 'Escape') e.preventDefault();
+        return;
+    }
+    if (e.key === 'Escape') {
+        e.preventDefault();
+        closeResetModal();
+    } else if (e.key === 'Enter') {
+        e.preventDefault();
+        submitReset();
+    }
+}
+
+async function submitReset() {
+    if (reset.busy || !reset.token) return;
+    const password = $('reset-password').value;
+    const again = $('reset-password-2').value;
+    const weak = passwordProblem(password);
+    if (weak) {
+        setModalMessage('reset-modal-message', weak, 'error');
+        refocus('reset-password');
+        return;
+    }
+    if (password !== again) {
+        setModalMessage('reset-modal-message', 'The two passwords differ', 'error');
+        refocus('reset-password-2');
+        return;
+    }
+    setResetBusy(true);
+    clearModalMessage('reset-modal-message');
+    let response;
+    try {
+        response = await apiJSON('POST', '/api/auth/reset', { token: reset.token, password });
+    } catch (error) {
+        setResetBusy(false);
+        setModalMessage('reset-modal-message', handleApiError('reset', error).statusMessage, 'error');
+        refocus('reset-password');
+        return;
+    }
+    if (!response.ok) {
+        const err = await parseErrorResponse(response);
+        setResetBusy(false);
+        setModalMessage('reset-modal-message', response.status === 400
+            ? (err.details && err.error === 'weak password' ? err.details : 'This link is invalid or has expired. Ask for a new one from Sign in.')
+            : (err.error || `Server error (${response.status})`), 'error');
+        refocus('reset-password');
+        return;
+    }
+    let result;
+    try {
+        result = await response.json();
+    } catch {
+        setResetBusy(false);
+        setModalMessage('reset-modal-message', 'Unexpected response from server', 'error');
+        return;
+    }
+    setSignedIn(result.userId, result.username, result.token);
+    setModalMessage('reset-modal-message', `Password changed — signed in as ${result.username}`, 'success');
+    setTimeout(() => {
+        setResetBusy(false);
+        closeResetModal();
+    }, MODAL_SUCCESS_DISPLAY_MS * 2);
+}
+
 async function handleRegister() {
     if (auth.busy) return;
     const username = $('register-username').value.trim();
@@ -655,17 +842,15 @@ async function handleRegister() {
         setModalMessage('auth-modal-message', 'Username and password required', 'error');
         return;
     }
-    if (password.length < 8) {
+    const weak = passwordProblem(password);
-        setModalMessage('auth-modal-message', 'Password needs at least 8 characters', 'error');
+    if (weak) {
-        return;
+        setModalMessage('auth-modal-message', weak, 'error');
-    }
+        refocus('register-password');
-    if (!/[a-zA-Z]/.test(password) || !/[0-9]/.test(password)) {
-        setModalMessage('auth-modal-message', 'Password needs a letter and a number', 'error');
         return;
     }
     const body = { username, password };
     if (email) body.email = email;
-    const result = await submitAuth('/api/auth/register', body, 'Registration failed');
+    const result = await submitAuth('/api/auth/register', body, 'Registration failed', 'register-password');
     if (!result) return;
     setSignedIn(result.userId, result.username, result.token);
     setModalMessage('auth-modal-message', `Account created, welcome ${result.username}`, 'success');
@@ -1344,26 +1529,32 @@ function updateTurnStrip() {
     const dot = $('turn-dot');
     const text = $('turn-text');
     let status = 'idle', label = 'No game';
+    let title = '';
     if (!live.gameId) {
         status = 'idle';
         label = 'No game';
     } else if (live.state === 'pending' || live.isLocked) {
         status = 'thinking';
-        label = 'Computer thinking…';
+        label = 'Thinking…';
+        title = 'The computer is thinking';
     } else if (isGameOver(live.state)) {
         status = live.state === 'white wins' ? 'white-wins' : live.state === 'black wins' ? 'black-wins' : live.state;
-        label = describeResult(live.state, live.termination);
+        label = shortResult(live.state, live.termination);
+        title = describeResult(live.state, live.termination);
     } else if (live.state === 'stuck') {
         status = 'stuck';
-        label = 'Engine error — undo or start a new game';
+        label = 'Engine error';
+        title = 'Engine error — undo or start a new game';
     } else {
+        // The dot shows the side to move; the text says whose it is.
         status = live.turn === 'w' ? 'white' : 'black';
         const side = live.turn === 'w' ? 'White' : 'Black';
-        label = live.turn === playerColor() ? `Your move (${side})` : `Computer to move (${side})`;
+        label = live.turn === playerColor() ? 'Your move' : 'Computer';
+        title = `${side} to move: ${live.turn === playerColor() ? 'you' : 'the computer'}`;
     }
     dot.dataset.status = status;
     text.textContent = label;
-    $('turn-strip').title = label;
+    $('turn-strip').title = title || label;
 }
 
 // Draw needs a game in progress with the board free; resigning only needs
@@ -2144,6 +2335,11 @@ function bindEvents() {
     });
     $('login-submit-btn').addEventListener('click', handleLogin);
     $('register-submit-btn').addEventListener('click', handleRegister);
+    $('forgot-btn').addEventListener('click', () => switchAuthTab('recover'));
+    $('recover-back-btn').addEventListener('click', () => switchAuthTab('login'));
+    $('recover-submit-btn').addEventListener('click', handleRecover);
+    $('reset-submit-btn').addEventListener('click', submitReset);
+    $('reset-cancel-btn').addEventListener('click', closeResetModal);
     $('auth-cancel-btn').addEventListener('click', hideAuthModal);
     $('auth-cancel-btn-2').addEventListener('click', hideAuthModal);
     $('logout-btn').addEventListener('click', handleLogoutClick);
@@ -2198,6 +2394,18 @@ document.addEventListener('DOMContentLoaded', async () => {
     updateTurnStrip();
     updateGameControls();
     startHealthCheck();
+    // A reset link: take the token off the address before anything else, so
+    // it is neither kept in history nor shared with a copied link.
+    const params = new URLSearchParams(location.search);
+    const resetToken = params.get('reset');
+    if (resetToken !== null) {
+        params.delete('reset');
+        const query = params.toString();
+        try {
+            history.replaceState({ chess: true }, '', location.pathname + (query ? `?${query}` : ''));
+        } catch { /* history blocked */ }
+    }
     await restoreAuthSession();
     await applyURL();
+    if (resetToken) openResetModal(resetToken);
 });

internal/server/webserver/chess-client-web/index.html

@@ -10,7 +10,31 @@
 <body data-mode="live">
 <div class="app">
     <header class="topbar">
-        <div class="brand" aria-label="Chess"><span class="brand-mark" aria-hidden="true">♞</span><span class="brand-name">Chess</span></div>
+        <div class="brand" aria-label="Chess">
+            <svg class="brand-mark" viewBox="41 34 430 430" aria-hidden="true" focusable="false">
+                <defs>
+                    <linearGradient id="brand-piece" x1="20%" y1="0%" x2="80%" y2="100%">
+                        <stop offset="0%" stop-color="#C8CDD6"/>
+                        <stop offset="45%" stop-color="#8B929E"/>
+                        <stop offset="100%" stop-color="#4F545D"/>
+                    </linearGradient>
+                </defs>
+                <g fill="url(#brand-piece)" stroke="#14161A" stroke-width="4" stroke-linejoin="round">
+                    <path d="M136 450Q256 465 376 450L346 410Q256 420 166 410Z"/>
+                    <path d="M166 410Q256 420 346 410L316 370Q256 380 196 370Z"/>
+                    <path d="M196 370Q256 380 316 370C300 290 286 230 282 205H230C226 230 212 290 196 370Z"/>
+                </g>
+                <path d="M330 90Q265 96 230 120Q265 144 335 150Z" fill="#111318"/>
+                <g stroke="#F0F2F5" stroke-width="6" stroke-linecap="round">
+                    <path d="M263.17 85V155M299.33 85V155"/>
+                </g>
+                <g fill="url(#brand-piece)" stroke="#14161A" stroke-width="4" stroke-linejoin="round">
+                    <path d="M226 200C150 180 150 70 256 40C290 50 315 65 330 90Q265 96 230 120Q265 144 335 150C335 170 315 190 286 200Z"/>
+                    <rect x="216" y="195" width="80" height="16" rx="8"/>
+                </g>
+            </svg>
+            <span class="brand-name">Chess</span>
+        </div>
         <div class="health" aria-label="Server status">
             <span class="dot" id="server-dot" data-status="unknown" title="Server: unknown" role="img" aria-label="Server: unknown"></span>
             <span class="dot" id="storage-dot" data-status="unknown" title="Storage: unknown" role="img" aria-label="Storage: unknown"></span>
@@ -44,7 +68,7 @@
                     <span class="turn-text" id="turn-text">No game</span>
                 </div>
                 <div class="controls" role="group" aria-label="Game controls">
-                    <button id="new-game-btn" class="btn btn-primary" type="button">New game</button>
+                    <button id="new-game-btn" class="btn btn-primary" type="button" title="New game">New</button>
                     <button id="undo-btn" class="btn btn-secondary" type="button" disabled>Undo</button>
                     <button id="draw-btn" class="btn btn-secondary" type="button" title="Offer a draw" disabled>Draw</button>
                     <button id="resign-btn" class="btn btn-secondary" type="button" title="Resign this game" disabled>Resign</button>
@@ -201,6 +225,19 @@
                 <button id="login-submit-btn" class="btn btn-primary" type="button">Sign in</button>
                 <button id="auth-cancel-btn" class="btn btn-secondary" type="button">Cancel</button>
             </div>
+            <p class="auth-aside hidden" id="forgot-row"><button id="forgot-btn" class="link-btn" type="button">Forgot password?</button></p>
+        </div>
+
+        <div id="recover-form" class="auth-form hidden">
+            <p class="auth-help">Enter your username or email. If the account has an email address, a link to choose a new password is sent to it; the link works for an hour.</p>
+            <div class="form-group">
+                <label for="recover-identifier">Username or email</label>
+                <input type="text" id="recover-identifier" autocomplete="username">
+            </div>
+            <div class="modal-buttons">
+                <button id="recover-submit-btn" class="btn btn-primary" type="button">Send reset link</button>
+                <button id="recover-back-btn" class="btn btn-secondary" type="button">Back</button>
+            </div>
         </div>
 
         <div id="register-form" class="auth-form hidden">
@@ -224,6 +261,26 @@
     </div>
 </div>
 
+<!-- Reset Modal: opened by the link in the recovery email (?reset=<token>) -->
+<div id="reset-overlay" class="modal-overlay">
+    <div class="modal auth-modal" role="dialog" aria-modal="true" aria-labelledby="reset-title">
+        <h2 id="reset-title">Choose a new password</h2>
+        <div id="reset-modal-message" class="modal-message" role="status" aria-live="polite"></div>
+        <div class="form-group">
+            <label for="reset-password">New password (8+ characters, a letter and a number)</label>
+            <input type="password" id="reset-password" autocomplete="new-password">
+        </div>
+        <div class="form-group">
+            <label for="reset-password-2">Repeat the password</label>
+            <input type="password" id="reset-password-2" autocomplete="new-password">
+        </div>
+        <div class="modal-buttons">
+            <button id="reset-submit-btn" class="btn btn-primary" type="button">Set password</button>
+            <button id="reset-cancel-btn" class="btn btn-secondary" type="button">Cancel</button>
+        </div>
+    </div>
+</div>
+
 <!-- Account Modal: shown instead of the login modal while signed in -->
 <div id="account-overlay" class="modal-overlay">
     <div class="modal account-modal" role="dialog" aria-modal="true" aria-labelledby="account-title">

internal/server/webserver/chess-client-web/style.css

@@ -125,9 +125,9 @@ button { cursor: pointer; }
 }
 
 .brand-mark {
-    font-size: 1.35rem;
+    width: 1.5rem;
-    line-height: 1;
+    height: 1.5rem;
-    color: var(--periwinkle);
+    flex: none;
 }
 
 .health {
@@ -722,6 +722,7 @@ input[type="range"]:focus-visible { outline: 2px solid var(--periwinkle); outlin
 .auth-form input[type="text"],
 .auth-form input[type="email"],
 .auth-form input[type="password"],
+#reset-overlay input[type="password"],
 .account-form input[type="password"] {
     width: 100%;
     padding: 0.5rem 0.6rem;
@@ -740,7 +741,7 @@ input[type="range"]:focus-visible { outline: 2px solid var(--periwinkle); outlin
     word-wrap: break-word;
 }
 
-.fen-input:focus, .auth-form input:focus, .account-form input:focus {
+.fen-input:focus, .auth-form input:focus, .account-form input:focus, #reset-overlay input:focus {
     outline: none;
     border-color: var(--royal);
 }
@@ -754,6 +755,33 @@ input[type="range"]:focus-visible { outline: 2px solid var(--periwinkle); outlin
 
 .auth-modal, .account-modal { max-width: 360px; }
 
+.auth-aside {
+    margin: 0.9rem 0 0;
+    text-align: center;
+    font-size: 0.85rem;
+}
+
+.auth-help {
+    margin: 0 0 0.9rem;
+    font-size: 0.85rem;
+    line-height: 1.45;
+    color: var(--muted);
+}
+
+.link-btn {
+    padding: 0;
+    background: none;
+    border: none;
+    color: var(--periwinkle);
+    text-decoration: underline;
+    text-underline-offset: 2px;
+    cursor: pointer;
+}
+
+.link-btn:hover { color: var(--fg); }
+.link-btn:focus-visible { outline: 2px solid var(--periwinkle); outline-offset: 2px; border-radius: 2px; }
+.auth-form input[type="password"]#reset-password, .auth-form input[type="password"]#reset-password-2 { width: 100%; }
+
 .auth-tabs {
     display: flex;
     margin-bottom: 0.9rem;
@@ -1007,7 +1035,7 @@ input[type="range"]:focus-visible { outline: 2px solid var(--periwinkle); outlin
 
 /* --- Stacked layout (board over panel) -------------------------------- */
 
-@media (max-width: 978px) {
+@media (min-width: 641px) and (max-width: 978px) {
     :root {
         --panel-width: clamp(360px, 45vw, 440px);
         --panel-height: 230px;
@@ -1036,12 +1064,18 @@ input[type="range"]:focus-visible { outline: 2px solid var(--periwinkle); outlin
 
     .pane {
         display: grid;
-        grid-template-columns: clamp(150px, 18.4vw, 180px) 1fr;
+        grid-template-columns: clamp(150px, 18.4vw, 180px) minmax(0, 1fr);
         grid-template-rows: min-content 1fr;
         gap: 0.5rem 0.75rem;
         padding: 0.6rem;
     }
 
+    .pane > * { min-width: 0; }
+    .toolbar .btn-tool { min-width: 0; overflow: hidden; }
+    /* Four export buttons in the narrow right column: icons only. */
+    .pane-replay .toolbar .btn-tool span { display: none; }
+    .pane-replay .toolbar .btn-tool .icon { width: 1.2rem; height: 1.2rem; }
+
     body[data-mode="replay"] .pane-live, body[data-mode="live"] .pane-replay { display: none; }
 
     .pane-live .turn-strip { grid-column: 1; grid-row: 1; }
@@ -1086,19 +1120,111 @@ input[type="range"]:focus-visible { outline: 2px solid var(--periwinkle); outlin
     .btn-tool { font-size: 0.74rem; padding: 0.3rem 0.2rem; }
 }
 
-@media (max-width: 530px) {
+/* --- Phone layout: full-width rows, edge to edge ------------------------ */
+
+@media (max-width: 640px) {
     :root {
-        --panel-width: min(92vw, 440px);
+        /* Reserve under the board: top bar 40 + gap 6 + turn strip 32 +
-        --board-edge: max(240px, min(min(92vw, 440px), calc(100vh - 332px)));
+           controls 36 + move list 96 + toolbar 36 + gaps and padding 26 =
-        --board-pad: 12px;
+           276. Small viewport units, so the browser's bars never cover the
+           panel. The replay pane is taller (head, navigation, export, exit),
+           so a replay reserves more and the board gives way on a short
+           screen rather than the controls dropping below the fold. */
+        --board-edge: max(240px, min(100vw, calc(100svh - 284px)));
+        --board-pad: 14px;
+        --panel-width: 100%;
+        --panel-height: auto;
+        --topbar-height: 2.5rem;
+    }
+
+    body { overflow-y: auto; overflow-x: hidden; }
+    body[data-mode="replay"] { --board-edge: max(240px, min(100vw, calc(100svh - 372px))); }
+
+    /* The app is exactly the viewport, so the panel and its move list shrink
+       to fit; only when their minimums do not fit does the page scroll. */
+    .app { padding: 0; gap: 6px; height: 100svh; min-height: 100svh; overflow: visible; }
+
+    .topbar {
+        border-radius: 0;
+        border-left: none;
+        border-right: none;
+        border-top: none;
+        padding: 0 0.6rem;
     }
 
     .brand-name, #games-btn span, #auth-label { display: none; }
-    /* Icon-only export row in the replay pane: four buttons in 190px. */
+    #games-btn, #auth-btn { padding: 0.35rem 0.55rem; }
-    .pane-replay .toolbar .btn-tool span { display: none; }
+
-    .pane-replay .toolbar .btn-tool .icon { width: 1.2rem; height: 1.2rem; }
+    .workspace {
-    #games-btn, #auth-btn { padding: 0.35rem 0.5rem; }
+        flex: 1 1 auto;
-    .pane { grid-template-columns: 140px 1fr; }
+        min-height: 0;
+        flex-direction: column;
+        justify-content: flex-start;
+        gap: 6px;
+        overflow: visible;
+    }
+
+    .board-area { flex: none; }
+
+    .board-area { padding: var(--board-pad) 6px 6px 16px; }
+    .board-wrapper {
+        width: calc(var(--board-edge) - 22px);
+        height: calc(var(--board-edge) - 22px);
+    }
+    .coordinates.ranks { left: -14px; }
+    .coordinates.files { top: -15px; }
+
+    .panel {
+        display: flex;
+        flex-direction: column;
+        width: 100%;
+        flex: 1 1 auto;
+        min-height: 0;
+        height: auto;
+        border-radius: 0;
+        border-left: none;
+        border-right: none;
+        border-bottom: none;
+    }
+
+    .pane, .pane-live, .pane-replay {
+        display: flex;
+        flex: 1 1 auto;
+        flex-direction: column;
+        gap: 0.4rem;
+        padding: 0.5rem 0.6rem 0.6rem;
+        height: auto;
+    }
+
+    .pane > * { min-width: 0; }
+
+    .turn-strip { min-height: 2rem; padding: 0.25rem 0.6rem; }
+
+    .pane-live .controls {
+        grid-template-columns: repeat(4, 1fr);
+        grid-template-rows: auto;
+        gap: 0.35rem;
+    }
+    .pane-live .controls .btn { padding: 0.5rem 0.2rem; font-size: 0.85rem; min-height: 2.25rem; height: auto; }
+
+    .moves { flex: 1 1 auto; min-height: 96px; }
+    .move-grid { grid-template-columns: 2.2rem 1fr 1fr; font-size: 0.9rem; }
+
+    .toolbar .btn-tool { padding: 0.45rem 0.3rem; font-size: 0.82rem; min-width: 0; }
+
+    /* Replay: head, list, navigation, export and exit as rows. */
+    .pane-replay .replay-head { padding: 0.35rem 0.6rem; }
+    .pane-replay .replay-meta { display: none; }
+    .pane-replay .replay-nav {
+        display: grid;
+        grid-template-columns: repeat(5, 1fr) 1.4fr 1fr;
+        gap: 0.3rem;
+    }
+    .pane-replay .replay-nav .speed { margin: 0; }
+    .pane-replay .replay-nav .speed select { width: 100%; }
+    .pane-replay .btn-nav { width: 100%; height: 2.2rem; }
+    .pane-replay #replay-exit { padding: 0.5rem; font-size: 0.85rem; }
+
     .games-modal { padding: 0.75rem; }
     .game-row { gap: 0.5rem; padding: 0.4rem; }
     .mini-board { width: 56px; height: 56px; }
@@ -1106,6 +1232,13 @@ input[type="range"]:focus-visible { outline: 2px solid var(--periwinkle); outlin
     .modal-overlay { padding: 0.5rem; }
 }
 
+/* Very narrow phones: icon-only export buttons. */
+@media (max-width: 380px) {
+    .pane-replay .toolbar .btn-tool span { display: none; }
+    .pane-replay .toolbar .btn-tool .icon { width: 1.2rem; height: 1.2rem; }
+    .pane-live .controls .btn { font-size: 0.8rem; }
+}
+
 /* --- Motion ---------------------------------------------------------- */
 
 @media (prefers-reduced-motion: reduce) {

test/README.md

@@ -38,11 +38,12 @@ The server runs with `-dev`, debug logging, HTTP request logging, and relaxed ra
 It drops the test tables on exit, so it's preferred for clean testing.
 Can be used for all the tests.
 
-Logging can be adjusted without editing the script, and `WEB_PORT` also
+Logging can be adjusted without editing the script; `WEB_PORT` also serves
-serves the embedded web client (needed by the end-to-end suite):
+the embedded web client and `MAIL_DIR` turns on password recovery with the
+email written to that directory (both used by the end-to-end suite):
 ```bash
 LOG_LEVEL=info LOG_HTTP=false test/run-test-server.sh bin/chess-server
-WEB_PORT=9090 test/run-test-server.sh bin/chess-server
+WEB_PORT=9090 MAIL_DIR=/tmp/chess-mail test/run-test-server.sh bin/chess-server
 ```
 
 ### Pre-configured Users
@@ -226,20 +227,22 @@ Playwright drives the embedded web client in Chromium against a running
 server with PostgreSQL and Stockfish: it plays a short game, lists it under
 My games, replays it with the buttons and the keyboard, autoplays to the end,
 compares the FEN and PGN it exports (copy and download) with the API, follows
-a deep link to a checkmate, steps back through the browser history, and
+a deep link to a checkmate, steps back through the browser history, replays
-replays an anonymous game from the device list.
+an anonymous game from the device list, checks that a phone-sized viewport
+holds the board and the controls without scrolling, and resets a forgotten
+password through the link in the emailed message (needs `MAIL_DIR`).
 
 Requirements: Node.js 20+ and a Chromium that Playwright can run.
 
 ```bash
-# Terminal 1: the test server with the web client
+# Terminal 1: the test server with the web client and mail to a directory
-WEB_PORT=9090 test/run-test-server.sh bin/chess-server
+WEB_PORT=9090 MAIL_DIR=/tmp/chess-mail test/run-test-server.sh bin/chess-server
 
 # Terminal 2, once
 cd test/e2e && npm install && npx playwright install chromium
 
 # Terminal 2: run
-npm test                      # or, from the repository root: make test-e2e
+CHESS_E2E_MAIL_DIR=/tmp/chess-mail npm test   # or, from the repository root: make test-e2e
 ```
 
 Environment:
@@ -249,6 +252,9 @@ Environment:
   to register users, create games and fetch what the client should export
 - `CHESS_E2E_CHROMIUM`: path to a Chromium binary when
   `npx playwright install` is not possible (an already installed browser)
+- `CHESS_E2E_MAIL_DIR`: the server's `-mail-dir` (`MAIL_DIR` of the test
+  server); the password-reset test reads the link from the newest file and
+  is skipped when unset
 
 Each test registers its own user or plays anonymously, so the suite can be
 repeated against the same server. The engine plays at level 0 with a 100 ms

test/e2e/replay.spec.js

@@ -6,6 +6,11 @@
 const { test, expect } = require('@playwright/test');
 
 const API = process.env.CHESS_E2E_API || 'http://localhost:8080';
+// Where the server writes password-reset email (-mail-dir); the reset test
+// is skipped without it.
+const MAIL_DIR = process.env.CHESS_E2E_MAIL_DIR || '';
+const fs = require('fs');
+const path = require('path');
 const START_FEN = 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1';
 
 // The engine level and search time are set through the sliders' inputs.
@@ -174,6 +179,90 @@ test.describe('web replay', () => {
         await expect(page).toHaveURL(/\/$/);
     });
 
+    test('a phone fits the board and the controls without scrolling', async ({ browser }) => {
+        const context = await browser.newContext({ viewport: { width: 412, height: 780 }, isMobile: true, hasTouch: true });
+        const page = await context.newPage();
+        await page.goto('/');
+        const fits = () => page.evaluate(() => ({
+            w: document.documentElement.scrollWidth <= innerWidth,
+            h: document.documentElement.scrollHeight <= innerHeight,
+        }));
+        expect(await fits()).toEqual({ w: true, h: true });
+        // The controls sit in one row of short labels.
+        await expect(page.locator('#new-game-btn')).toHaveText('New');
+        const [newBox, resignBox] = await Promise.all([
+            page.locator('#new-game-btn').boundingBox(), page.locator('#resign-btn').boundingBox()]);
+        expect(Math.abs(newBox.y - resignBox.y)).toBeLessThan(2);
+        expect(newBox.height).toBeLessThan(50);
+        await expect(page.locator('.pane-live .toolbar')).toBeInViewport();
+        // A replay keeps its controls on screen too.
+        const created = await (await context.request.post(`${API}/api/games`, { data: { white: { type: 1 }, black: { type: 1 } } })).json();
+        await context.request.post(`${API}/api/games/${created.gameId}/moves`, { data: { move: 'e2e4' } });
+        await page.goto(`/?replay=${created.gameId}&ply=1`);
+        await expect(page.locator('body')).toHaveAttribute('data-mode', 'replay');
+        expect(await fits()).toEqual({ w: true, h: true });
+        await expect(page.locator('#replay-exit')).toBeInViewport();
+        await expect(page.locator('#replay-link')).toBeInViewport();
+        await context.close();
+    });
+
+    test('a forgotten password is reset through the emailed link', async ({ page, request }) => {
+        test.skip(!MAIL_DIR, 'CHESS_E2E_MAIL_DIR is not set (start the server with MAIL_DIR)');
+        const username = `reset${Date.now().toString(36)}${Math.floor(Math.random() * 1000)}`;
+        const email = `${username}@example.test`;
+        const created = await request.post(`${API}/api/auth/register`, {
+            data: { username, email, password: 'OldPass123' },
+        });
+        expect(created.status(), await created.text()).toBe(201);
+
+        await page.goto('/');
+        await expect(page.locator('#storage-dot')).toHaveAttribute('data-status', 'ok');
+        await page.click('#auth-btn');
+        // A wrong password keeps the focus in the password field.
+        await page.fill('#login-identifier', username);
+        await page.fill('#login-password', 'wrong');
+        await page.click('#login-submit-btn');
+        await expect(page.locator('#auth-modal-message')).toContainText('Wrong username or password');
+        await expect(page.locator('#login-password')).toBeFocused();
+
+        await expect(page.locator('#forgot-btn')).toBeVisible();
+        await page.click('#forgot-btn');
+        await page.fill('#recover-identifier', email);
+        const mails = () => (fs.existsSync(MAIL_DIR) ? fs.readdirSync(MAIL_DIR) : []);
+        const before = mails().length;
+        await page.click('#recover-submit-btn');
+        await expect(page.locator('#auth-modal-message')).toContainText('on its way');
+        await expect.poll(() => mails().length, { timeout: 10_000 }).toBeGreaterThan(before);
+        const files = fs.readdirSync(MAIL_DIR).map(f => path.join(MAIL_DIR, f))
+            .sort((a, b) => fs.statSync(b).mtimeMs - fs.statSync(a).mtimeMs);
+        const mail = fs.readFileSync(files[0], 'utf8');
+        expect(mail).toContain(`To: ${email}`);
+        const link = /(https?:\/\/\S+\?reset=[A-Za-z0-9_-]+)/.exec(mail)[1];
+        const origin = new URL(page.url()).origin;
+        await page.goto(link.replace(/^https?:\/\/[^/]+/, origin));
+        await expect(page.locator('#reset-overlay')).toHaveClass(/show/);
+        // The token is removed from the address at once.
+        expect(page.url()).not.toContain('reset=');
+        await page.fill('#reset-password', 'NewPass123');
+        await page.fill('#reset-password-2', 'NewPass124');
+        await page.click('#reset-submit-btn');
+        await expect(page.locator('#reset-modal-message')).toContainText('differ');
+        await page.fill('#reset-password-2', 'NewPass123');
+        await page.keyboard.press('Enter');
+        await expect(page.locator('#auth-label')).toHaveText(username);
+        await expect(page.locator('#reset-overlay')).not.toHaveClass(/show/, { timeout: 5_000 });
+        // The old password is gone, the new one and the link are not reusable.
+        const old = await request.post(`${API}/api/auth/login`, { data: { identifier: username, password: 'OldPass123' } });
+        expect(old.status()).toBe(401);
+        const fresh = await request.post(`${API}/api/auth/login`, { data: { identifier: username, password: 'NewPass123' } });
+        expect(fresh.status()).toBe(200);
+        await page.goto(link.replace(/^https?:\/\/[^/]+/, origin));
+        await page.fill('#reset-password', 'NewPass125');
+        await page.fill('#reset-password-2', 'NewPass125');
+        await page.click('#reset-submit-btn');
+        await expect(page.locator('#reset-modal-message')).toContainText('invalid or has expired');
+    });
+
     test('an anonymous visitor replays from the device list', async ({ page }) => {
         await page.goto('/');
         await expect(page.locator('#auth-label')).toHaveText('Sign in');
@@ -193,6 +282,7 @@ test.describe('web replay', () => {
         await expect(page.locator('.coordinates.ranks span').first()).toHaveText('1');
         expect(await page.evaluate(() => replay.history.initialFen)).toBe(START_FEN);
         await page.click('#replay-exit');
-        await expect(page.locator('#turn-text')).toContainText('Your move (Black)');
+        await expect(page.locator('#turn-text')).toHaveText('Your move');
+        await expect(page.locator('#turn-dot')).toHaveAttribute('data-status', 'black');
     });
 });

test/run-test-server.sh

@@ -10,8 +10,11 @@ CHESS_SERVER_EXEC=${1:-"bin/chess-server"}
 export CHESS_DSN="$CHESS_TEST_DSN"
 PID_FILE="/tmp/chess-server_test.pid"
 API_PORT=${API_PORT:-8080}
-# Set WEB_PORT to also serve the embedded web client (for test/e2e).
+# Set WEB_PORT to also serve the embedded web client (for test/e2e), and
+# MAIL_DIR to enable password recovery with the email written to that
+# directory instead of sent.
 WEB_PORT=${WEB_PORT:-}
+MAIL_DIR=${MAIL_DIR:-}
 LOG_LEVEL=${LOG_LEVEL:-debug}
 LOG_HTTP=${LOG_HTTP:-true}
 
@@ -98,6 +101,7 @@ echo "Configuration:"
 echo "  Executable: $CHESS_SERVER_EXEC"
 echo "  Database:   \$CHESS_TEST_DSN (tables dropped on exit)"
 echo "  Port:       $API_PORT${WEB_PORT:+ (web client on $WEB_PORT)}"
+echo "  Mail:       ${MAIL_DIR:-off (set MAIL_DIR for password recovery)}"
 echo "  Mode:       Development (relaxed rate limits; PostgreSQL storage)"
 echo "  Log level:  $LOG_LEVEL (HTTP requests: $LOG_HTTP)"
 echo "  Purpose:    Backend for chess-server tests"
@@ -115,6 +119,11 @@ echo ""
 # Start chess-server in foreground with dev mode and storage
 WEB_FLAGS=()
 [ -n "$WEB_PORT" ] && WEB_FLAGS=(-serve -web-port "$WEB_PORT")
+if [ -n "$MAIL_DIR" ]; then
+    mkdir -p "$MAIL_DIR"
+    WEB_FLAGS+=(-mail-dir "$MAIL_DIR" -mail-from "Chess <chess@localhost>" \
+        -public-url "http://localhost:${WEB_PORT:-9090}/")
+fi
 "$CHESS_SERVER_EXEC" \
 	-dev \
 	-log-level "$LOG_LEVEL" \

web/chess-client-wasm/terminal.js

@@ -56,6 +56,13 @@
     const fitAddon = new FitAddon.FitAddon();
     term.loadAddon(fitAddon);
 
+    // The client pages long output by the terminal's size, read from here
+    // (display/termsize_wasm.go).
+    globalThis.chessTerminal = {
+        get rows() { return term.rows; },
+        get cols() { return term.cols; }
+    };
+
     term.open(screenEl);
 
     // WebGL must load after open(); the DOM renderer is the fallback.