v0.13.3 account delete api, web client and toolchain update

internal/server/game/game.go

@@ -406,6 +406,20 @@ func (g *Game) ClaimSlot(color core.Color, userID string) error {
 	return nil
 }
 
+// ReleaseUser clears userID's claims and name snapshots, leaving those slots
+// anonymous, and reports whether any slot changed. Player IDs stay: once the
+// account is gone they identify nobody. Caller must hold the lock.
+func (g *Game) ReleaseUser(userID string) bool {
+	changed := false
+	for _, player := range g.players {
+		if player != nil && player.ClaimedBy == userID {
+			player.ClaimedBy, player.Name = "", ""
+			changed = true
+		}
+	}
+	return changed
+}
+
 // GetSlotOwner returns the userID that claimed the slot, empty if unclaimed
 // Caller must hold the lock
 func (g *Game) GetSlotOwner(color core.Color) string {

internal/server/http/auth.go

@@ -30,6 +30,11 @@ type LoginRequest struct {
 	Password   string `json:"password" validate:"required"`
 }
 
+// DeleteAccountRequest re-confirms the password before an account is deleted.
+type DeleteAccountRequest struct {
+	Password string `json:"password" validate:"required"`
+}
+
 // AuthResponse contains JWT token and user information
 type AuthResponse struct {
 	Token     string    `json:"token"`
@@ -269,3 +274,51 @@ func (h *HTTPHandler) LogoutHandler(c *fiber.Ctx) error {
 
 	return c.JSON(fiber.Map{"message": "logged out"})
 }
+
+// DeleteAccountHandler deletes the caller's account after re-checking the
+// password. The caller's games lose the claim and the name; see
+// Service.DeleteAccount.
+func (h *HTTPHandler) DeleteAccountHandler(c *fiber.Ctx) error {
+	userID, _ := c.Locals("userID").(string)
+	sessionID, _ := c.Locals("sessionID").(string)
+	if userID == "" || sessionID == "" {
+		return c.Status(fiber.StatusUnauthorized).JSON(core.ErrorResponse{
+			Error: "unauthorized",
+			Code:  core.ErrInvalidRequest,
+		})
+	}
+
+	var req DeleteAccountRequest
+	if err := c.BodyParser(&req); err != nil || req.Password == "" {
+		return c.Status(fiber.StatusBadRequest).JSON(core.ErrorResponse{
+			Error:   "invalid request body",
+			Code:    core.ErrInvalidRequest,
+			Details: "password is required to delete the account",
+		})
+	}
+
+	if err := h.svc.DeleteAccount(userID, sessionID, req.Password); err != nil {
+		switch {
+		case errors.Is(err, service.ErrInvalidCredentials):
+			return c.Status(fiber.StatusUnauthorized).JSON(core.ErrorResponse{
+				Error: "invalid credentials",
+				Code:  core.ErrInvalidRequest,
+			})
+		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 delete account",
+				Code:  core.ErrInternalError,
+			})
+		}
+	}
+
+	return c.SendStatus(fiber.StatusNoContent)
+}

internal/server/http/handler.go

@@ -145,6 +145,22 @@ func NewFiberApp(proc *processor.Processor, svc *service.Service, opts Options)
 	// Logout
 	auth.Post("/logout", AuthRequired(validateToken), h.LogoutHandler)
 
+	// Delete own account: 5 req/min per IP. It takes a password, so it is
+	// limited like login; authentication runs first, so only a signed-in
+	// caller reaches the password check.
+	auth.Delete("/me", AuthRequired(validateToken), limiter.New(limiter.Config{
+		Max:          5,
+		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: "5 account deletion attempts per minute allowed",
+			})
+		},
+	}), h.DeleteAccountHandler)
+
 	// Game routes with standard rate limiting
 	maxReq := rateLimitRate
 	if devMode {

internal/server/http/handler_test.go

@@ -88,6 +88,7 @@ func TestAPIRoutes(t *testing.T) {
 		"POST /api/auth/login",
 		"GET /api/auth/me",
 		"POST /api/auth/logout",
+		"DELETE /api/auth/me",
 		"POST /api/games",
 		"GET /api/games/:gameId",
 		"GET /api/games/:gameId/history",
@@ -212,3 +213,74 @@ func TestStoredGameEndpoints(t *testing.T) {
 		}
 	}
 }
+
+func TestDeleteAccountRequiresPasswordAndEndsTheSession(t *testing.T) {
+	store, err := storage.NewStore(pgtest.DSN(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := store.InitDB(); err != nil {
+		t.Fatal(err)
+	}
+	svc, err := service.New(store, []byte("test-secret-test-secret-test-secret"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { svc.Shutdown(time.Second) })
+	app := NewFiberApp(nil, svc, Options{DevMode: true})
+
+	send := func(method, path, token, body string) int {
+		t.Helper()
+		var reader io.Reader
+		if body != "" {
+			reader = strings.NewReader(body)
+		}
+		request := httptest.NewRequest(method, path, reader)
+		if body != "" {
+			request.Header.Set("Content-Type", "application/json")
+		}
+		if token != "" {
+			request.Header.Set("Authorization", "Bearer "+token)
+		}
+		response, err := app.Test(request, 10_000)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return response.StatusCode
+	}
+
+	user, sessionID, err := svc.RegisterUser("alice", "", "Password1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	token, err := svc.GenerateUserToken(user.UserID, sessionID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for name, test := range map[string]struct {
+		token, body string
+		want        int
+	}{
+		"no token":       {"", `{"password":"Password1"}`, 401},
+		"no password":    {token, `{}`, 400},
+		"wrong password": {token, `{"password":"Password2"}`, 401},
+	} {
+		if got := send("DELETE", "/api/auth/me", test.token, test.body); got != test.want {
+			t.Errorf("%s: status %d, want %d", name, got, test.want)
+		}
+	}
+	if got := send("GET", "/api/auth/me", token, ""); got != 200 {
+		t.Fatalf("a refused deletion must leave the account working: /auth/me = %d", got)
+	}
+
+	if got := send("DELETE", "/api/auth/me", token, `{"password":"Password1"}`); got != 204 {
+		t.Fatalf("delete: status %d, want 204", got)
+	}
+	if got := send("GET", "/api/auth/me", token, ""); got != 401 {
+		t.Errorf("token still accepted after deletion: /auth/me = %d", got)
+	}
+	if _, _, err := svc.AuthenticateUser("alice", "Password1"); err == nil {
+		t.Error("deleted account can still sign in")
+	}
+}

internal/server/service/user.go

@@ -203,6 +203,56 @@ func (s *Service) InvalidateSession(sessionID string) error {
 	return nil
 }
 
+// DeleteAccount deletes the caller's own account after re-checking the
+// password, so a token left on an unattended device is not enough. The
+// session goes first, so no new request can act for the account; then the
+// account's claims are released on every game in memory, then the store
+// clears them from stored games and deletes the account, behind any gameplay
+// write already queued. Games nobody else claimed are anonymous from then on
+// and are purged after the usual inactivity window.
+func (s *Service) DeleteAccount(userID, sessionID, password string) error {
+	if s.store == nil {
+		return ErrStorageDisabled
+	}
+	record, err := s.store.GetUserByID(userID)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return ErrInvalidCredentials
+		}
+		return fmt.Errorf("%w: look up user: %v", ErrStorageUnavailable, err)
+	}
+	if err := s.verifyPassword(password, record.PasswordHash); err != nil {
+		if errors.Is(err, ErrAuthBusy) {
+			return err
+		}
+		return ErrInvalidCredentials
+	}
+
+	if err := s.store.DeleteSession(sessionID); err != nil {
+		return fmt.Errorf("%w: end session: %v", ErrStorageUnavailable, err)
+	}
+	released := s.releaseClaims(userID)
+	if err := s.store.DeleteAccount(userID); err != nil && !errors.Is(err, sql.ErrNoRows) {
+		return fmt.Errorf("%w: delete account: %v", ErrStorageUnavailable, err)
+	}
+	slog.Info("account deleted by its owner", "user_id", userID, "live_games_released", released)
+	return nil
+}
+
+// releaseClaims makes userID's slots anonymous in every game in memory and
+// returns how many games changed.
+func (s *Service) releaseClaims(userID string) int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	released := 0
+	for _, g := range s.games {
+		if g.ReleaseUser(userID) {
+			released++
+		}
+	}
+	return released
+}
+
 // GetUserByID retrieves user information by user ID
 func (s *Service) GetUserByID(userID string) (*User, error) {
 	if s.store == nil {

internal/server/service/user_test.go

@@ -5,6 +5,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/lixenwraith/chess/internal/server/chess"
+	"github.com/lixenwraith/chess/internal/server/core"
 	"github.com/lixenwraith/chess/internal/server/storage"
 
 	"github.com/google/uuid"
@@ -146,3 +148,44 @@ func TestNewRejectsShortJWTSecret(t *testing.T) {
 		t.Fatal("31-byte JWT secret accepted")
 	}
 }
+
+func TestDeleteAccountReleasesLiveClaims(t *testing.T) {
+	svc := newPersistentTestService(t)
+	user, sessionID, err := svc.RegisterUser("alice", "", "Password1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	token, err := svc.GenerateUserToken(user.UserID, sessionID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gameID := uuid.NewString()
+	white := core.NewPlayer(core.PlayerConfig{Type: core.PlayerHuman}, core.ColorWhite)
+	white.ID, white.ClaimedBy = user.UserID, user.UserID
+	black := core.NewPlayer(core.PlayerConfig{Type: core.PlayerComputer, Level: 1, SearchTime: 100}, core.ColorBlack)
+	if err := svc.CreateGame(gameID, white, black, chess.StartFEN, core.ColorWhite, core.StateOngoing, core.TermNone); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := svc.DeleteAccount(user.UserID, sessionID, "Password2"); !errors.Is(err, ErrInvalidCredentials) {
+		t.Fatalf("wrong password: %v, want ErrInvalidCredentials", err)
+	}
+	if _, _, err := svc.ValidateToken(token); err != nil {
+		t.Fatalf("a refused deletion ended the session: %v", err)
+	}
+
+	if err := svc.DeleteAccount(user.UserID, sessionID, "Password1"); err != nil {
+		t.Fatal(err)
+	}
+	if _, _, err := svc.ValidateToken(token); err == nil {
+		t.Error("token still valid after deletion")
+	}
+	view, err := svc.GetGameView(gameID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if owner := view.WhitePlayer.ClaimedBy; owner != "" {
+		t.Errorf("live game still claimed by the deleted account: %q", owner)
+	}
+}

internal/server/storage/storage.go

@@ -284,6 +284,37 @@ func (s *Store) enqueue(operation, gameID string, fn func(context.Context, *sql.
 	}
 }
 
+// enqueueWait queues fn on the ordered writer and waits for its own outcome,
+// for a write that must be ordered after queued gameplay writes and must also
+// report success only once it is durable.
+func (s *Store) enqueueWait(ctx context.Context, operation string, fn func(context.Context, *sql.Tx) error) error {
+	s.enqueueMu.RLock()
+	if s.closed.Load() {
+		s.enqueueMu.RUnlock()
+		return ErrStoreClosed
+	}
+	if !s.healthStatus.Load() {
+		s.enqueueMu.RUnlock()
+		return ErrStorageDegraded
+	}
+
+	done := make(chan error, 1)
+	select {
+	case s.writeChan <- writeRequest{operation: operation, run: fn, barrier: done}:
+		s.enqueueMu.RUnlock()
+	case <-ctx.Done():
+		s.enqueueMu.RUnlock()
+		return ctx.Err()
+	}
+
+	select {
+	case err := <-done:
+		return err
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
 // Flush waits until every write queued before this call has completed. Replay
 // reads use this barrier to provide read-after-write consistency while normal
 // gameplay retains the low-latency async write path.

internal/server/storage/storage_test.go

@@ -837,6 +837,75 @@ func TestClaimsSnapshotPlayerNames(t *testing.T) {
 	}
 }
 
+func TestDeleteAccountClearsClaimsAndNames(t *testing.T) {
+	store := openStore(t, pgtest.DSN(t))
+	now := time.Now().UTC()
+	alice, bob := uuid.NewString(), uuid.NewString()
+	for id, name := range map[string]string{alice: "alice", bob: "bob"} {
+		if err := store.CreateUser(UserRecord{UserID: id, Username: name, PasswordHash: "hash", CreatedAt: now}); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if err := store.CreateSession(SessionRecord{
+		SessionID: uuid.NewString(), UserID: alice, CreatedAt: now, ExpiresAt: now.Add(time.Hour),
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	// Alice against Bob, and Alice alone against the computer.
+	shared, solo := uuid.NewString(), uuid.NewString()
+	for _, record := range []GameRecord{
+		{GameID: shared, InitialFEN: "initial",
+			WhitePlayerID: alice, WhiteType: 1, WhiteClaimedBy: alice,
+			BlackPlayerID: bob, BlackType: 1, BlackClaimedBy: bob, StartTimeUTC: now},
+		{GameID: solo, InitialFEN: "initial",
+			WhitePlayerID: uuid.NewString(), WhiteType: 2,
+			BlackPlayerID: alice, BlackType: 1, BlackClaimedBy: alice, StartTimeUTC: now},
+	} {
+		if err := store.RecordNewGame(record); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	if err := store.DeleteAccount(alice); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := store.GetUserByID(alice); !errors.Is(err, sql.ErrNoRows) {
+		t.Fatalf("account still present: %v", err)
+	}
+	var sessions int
+	if err := store.db.QueryRow(`SELECT count(*) FROM sessions WHERE user_id = $1`, alice).Scan(&sessions); err != nil || sessions != 0 {
+		t.Fatalf("sessions left: %d, %v", sessions, err)
+	}
+
+	record, _, err := store.GetGameHistory(shared)
+	if err != nil || record.WhiteClaimedBy != "" || record.WhiteName != "" ||
+		record.BlackClaimedBy != bob || record.BlackName != "bob" {
+		t.Fatalf("shared game after deletion: white %q/%q black %q/%q, %v",
+			record.WhiteClaimedBy, record.WhiteName, record.BlackClaimedBy, record.BlackName, err)
+	}
+	// Nobody claims the solo game now, so the inactivity purge takes it.
+	if err := store.DeleteAnonymousGames(now.Add(time.Minute), nil); err != nil {
+		t.Fatal(err)
+	}
+	if err := store.Flush(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	if _, _, err := store.GetGameHistory(solo); !errors.Is(err, sql.ErrNoRows) {
+		t.Fatalf("solo game survived the anonymous purge: %v", err)
+	}
+	if _, _, err := store.GetGameHistory(shared); err != nil {
+		t.Fatalf("a game another user claims must stay: %v", err)
+	}
+
+	if err := store.DeleteAccount(alice); !errors.Is(err, sql.ErrNoRows) {
+		t.Fatalf("second deletion: %v, want sql.ErrNoRows", err)
+	}
+	if !store.IsHealthy() {
+		t.Fatal("deleting a missing account degraded the writer")
+	}
+}
+
 func timePointer(value time.Time) *time.Time {
 	return &value
 }

internal/server/storage/user.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"context"
 	"database/sql"
 	"errors"
 	"fmt"
@@ -124,6 +125,52 @@ func (s *Store) DeleteUser(userID string) error {
 	return nil
 }
 
+// DeleteAccount removes an account at its owner's request. Unlike DeleteUser,
+// which keeps the claim IDs and name snapshots for the record, it first clears
+// the user's claims and names from every stored game, so nothing in the
+// database still names the person, and a game nobody else claimed becomes
+// anonymous and falls to the inactivity purge. Sessions cascade.
+//
+// It runs on the ordered game writer, behind every gameplay write already
+// queued, so a queued claim cannot land on a game after it was cleared. It
+// returns sql.ErrNoRows when no such user exists.
+func (s *Store) DeleteAccount(userID string) error {
+	if !validUUID(userID) {
+		return sql.ErrNoRows
+	}
+	// Set inside the transaction, read after the writer reports back: the
+	// barrier channel orders the two. A missing row is an answer, not a
+	// failed write, so it must not degrade the writer.
+	var deleted int64
+	// Behind the queue, then its own transaction.
+	ctx, cancel := context.WithTimeout(context.Background(), flushTimeout+writeTimeout)
+	defer cancel()
+	err := s.enqueueWait(ctx, "delete_account", func(ctx context.Context, tx *sql.Tx) error {
+		if _, err := tx.ExecContext(ctx, `UPDATE games SET
+				white_claimed_by = CASE WHEN white_claimed_by = $1 THEN NULL ELSE white_claimed_by END,
+				white_name       = CASE WHEN white_claimed_by = $1 THEN NULL ELSE white_name END,
+				black_claimed_by = CASE WHEN black_claimed_by = $1 THEN NULL ELSE black_claimed_by END,
+				black_name       = CASE WHEN black_claimed_by = $1 THEN NULL ELSE black_name END
+			WHERE white_claimed_by = $1 OR black_claimed_by = $1`, userID); err != nil {
+			return err
+		}
+		result, err := tx.ExecContext(ctx, `DELETE FROM users WHERE user_id = $1`, userID)
+		if err != nil {
+			return err
+		}
+		deleted, err = result.RowsAffected()
+		return err
+	})
+	if err != nil {
+		return err
+	}
+	if deleted == 0 {
+		return sql.ErrNoRows
+	}
+	slog.Debug("storage account deleted", "user_id", userID)
+	return nil
+}
+
 // UpdateUserPassword updates user password hash
 func (s *Store) UpdateUserPassword(userID, passwordHash string) error {
 	return s.execUserUpdate(`UPDATE users SET password_hash = $2 WHERE user_id = $1`,

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

@@ -17,6 +17,7 @@ let gameState = {
     username: null,
     authBusy: false,
     newGameBusy: false,
+    accountBusy: false, // logout or account deletion in flight
     termination: '',
     actionBusy: false, // a draw or resign request is in flight
 };
@@ -85,6 +86,9 @@ document.getElementById('login-submit-btn').addEventListener('click', handleLogi
 document.getElementById('register-submit-btn').addEventListener('click', handleRegister);
 document.getElementById('auth-cancel-btn').addEventListener('click', hideAuthModal);
 document.getElementById('auth-cancel-btn-2').addEventListener('click', hideAuthModal);
+document.getElementById('logout-btn').addEventListener('click', handleLogoutClick);
+document.getElementById('account-cancel-btn').addEventListener('click', hideAccountModal);
+document.getElementById('delete-account-btn').addEventListener('click', deleteAccount);
 document.querySelectorAll('.promotion-choice').forEach(btn => {
     btn.addEventListener('click', () => closePromotion(btn.dataset.piece));
 });
@@ -143,15 +147,113 @@ function updateAuthIndicator(authenticated) {
 
 function handleAuthClick() {
     if (gameState.authToken) {
-        // Logged in - confirm logout
-        if (confirm(`Logout ${gameState.username}?`)) {
-            handleLogout();
-        }
+        showAccountModal();
     } else {
         showAuthModal();
     }
 }
 
+// Account dialog, for a signed-in user: log out, or delete the account. It
+// replaces a native confirm(), which a sandboxed embed may not be allowed.
+function showAccountModal() {
+    document.getElementById('account-username').textContent = gameState.username || '';
+    document.getElementById('delete-account').open = false;
+    document.getElementById('delete-password').value = '';
+    clearModalMessage('account-modal-message');
+    document.getElementById('account-overlay').classList.add('show');
+    document.removeEventListener('keydown', handleAccountKeydown);
+    document.addEventListener('keydown', handleAccountKeydown);
+    document.getElementById('account-cancel-btn').focus();
+}
+
+function hideAccountModal() {
+    if (gameState.accountBusy) return;
+    document.getElementById('account-overlay').classList.remove('show');
+    document.getElementById('delete-password').value = '';
+    document.removeEventListener('keydown', handleAccountKeydown);
+}
+
+function setAccountBusy(busy) {
+    gameState.accountBusy = busy;
+    for (const id of ['logout-btn', 'account-cancel-btn', 'delete-account-btn', 'delete-password']) {
+        document.getElementById(id).disabled = busy;
+    }
+}
+
+function handleAccountKeydown(e) {
+    if (gameState.accountBusy) {
+        if (e.key === 'Enter' || e.key === 'Escape') e.preventDefault();
+        return;
+    }
+    if (e.key === 'Escape') {
+        e.preventDefault();
+        hideAccountModal();
+    } else if (e.key === 'Enter' && document.activeElement?.id === 'delete-password') {
+        e.preventDefault();
+        deleteAccount();
+    }
+}
+
+async function handleLogoutClick() {
+    setAccountBusy(true);
+    await handleLogout();
+    setAccountBusy(false);
+    hideAccountModal();
+}
+
+// The server re-checks the password, ends the session, clears the account's
+// claims and names from its games, then deletes it (DELETE /api/auth/me).
+async function deleteAccount() {
+    if (gameState.accountBusy) return;
+    const password = document.getElementById('delete-password').value;
+    if (!password) {
+        setModalMessage('account-modal-message', 'Enter your password to delete the account', 'error');
+        return;
+    }
+
+    setAccountBusy(true);
+    clearModalMessage('account-modal-message');
+    let response;
+    try {
+        response = await authFetch(`${gameState.apiUrl}/api/auth/me`, {
+            method: 'DELETE',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ password }),
+        });
+    } catch {
+        setAccountBusy(false);
+        setModalMessage('account-modal-message', 'Network error: the account was not deleted', 'error');
+        return;
+    }
+
+    if (response.status === 204) {
+        const name = gameState.username;
+        clearAuthState();
+        setModalMessage('account-modal-message', `Account ${name} deleted`, 'success');
+        setTimeout(() => {
+            setAccountBusy(false);
+            hideAccountModal();
+        }, MODAL_SUCCESS_DISPLAY_MS * 2);
+        return;
+    }
+
+    setAccountBusy(false);
+    const data = await parseErrorResponse(response);
+    let message;
+    if (response.status === 401 && data.error === 'invalid credentials') {
+        message = 'Wrong password';
+    } else if (response.status === 401) {
+        // The token itself was refused: the session is already gone.
+        clearAuthState();
+        message = 'Your session has ended. Log in again to delete the account.';
+    } else if (response.status === 429) {
+        message = 'Too many attempts. Wait a minute and try again.';
+    } else {
+        message = data.error ? `Not deleted: ${data.error}` : `Server error (${response.status})`;
+    }
+    setModalMessage('account-modal-message', message, 'error');
+}
+
 // Disables/enables every interactive control in the auth modal at once, and tracks
 // whether a login/register request is in flight (or its success message is showing).
 // Guards re-entrancy from the Enter-key handler, which bypasses individual button

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

@@ -117,14 +117,40 @@
     </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">
+        <h2 id="account-title">Account</h2>
+        <div id="account-modal-message" class="modal-message" role="status" aria-live="polite"></div>
+        <p class="account-name">Signed in as <strong id="account-username"></strong></p>
+        <div class="modal-buttons">
+            <button id="logout-btn" class="btn btn-primary">Log out</button>
+            <button id="account-cancel-btn" class="btn btn-secondary">Close</button>
+        </div>
+        <details class="danger-zone" id="delete-account">
+            <summary>Delete account</summary>
+            <p>Deletes the account and signs you out. Your name and claim are removed
+            from every stored game; games nobody else plays are deleted 24 hours
+            after their last move. This cannot be undone.</p>
+            <div class="form-group account-form">
+                <label for="delete-password">Password</label>
+                <input type="password" id="delete-password" autocomplete="current-password">
+            </div>
+            <div class="modal-buttons">
+                <button id="delete-account-btn" class="btn btn-danger">Delete account</button>
+            </div>
+        </details>
+    </div>
+</div>
+
 <!-- Overlay Modal -->
 <div id="modal-overlay" class="modal-overlay">
     <div class="modal">
         <h2>New Game</h2>
-        <div id="new-game-modal-message" class="modal-message"></div>
-        <div class="form-group">
-            <label class="group-label">Your Color</label>
-            <div class="radio-group">
+        <div id="new-game-modal-message" class="modal-message" role="status" aria-live="polite"></div>
+        <div class="form-group form-row">
+            <span class="group-label" id="player-color-label">Your Color</span>
+            <div class="radio-group" role="radiogroup" aria-labelledby="player-color-label">
                 <label><input type="radio" name="player-color" value="white" checked><span>White</span></label>
                 <label><input type="radio" name="player-color" value="black"><span>Black</span></label>
             </div>

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

@@ -490,6 +490,16 @@ main {
     transform: translateY(-1px);
 }
 
+.btn-danger {
+    background: var(--tokyo-red);
+    color: var(--host-bg);
+}
+
+.btn-danger:hover:not(:disabled) {
+    filter: brightness(1.1);
+    transform: translateY(-1px);
+}
+
 .btn:disabled {
     opacity: 0.4;
     cursor: not-allowed;
@@ -546,7 +556,15 @@ main {
 }
 
 .form-group .group-label {
-    text-align: center;
+    color: var(--tokyo-cyan);
+}
+
+/* Label and control on one line: the colour choice. */
+.form-group.form-row {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 1rem;
 }
 
 .radio-group {
@@ -643,7 +661,8 @@ input[type="range"]::-webkit-slider-thumb {
 
 .auth-form input[type="text"],
 .auth-form input[type="email"],
-.auth-form input[type="password"] {
+.auth-form input[type="password"],
+.account-form input[type="password"] {
     width: 100%;
     padding: 0.5rem;
     background: var(--host-bg);
@@ -653,7 +672,8 @@ input[type="range"]::-webkit-slider-thumb {
     font-size: 0.9rem;
 }
 
-.auth-form input:focus {
+.auth-form input:focus,
+.account-form input:focus {
     outline: none;
     border-color: var(--host-royal);
 }
@@ -679,18 +699,29 @@ input[type="range"]::-webkit-slider-thumb {
     color: var(--tokyo-green);
 }
 
-/* --- Modal status message (Issue 2) --- */
+/* --- Modal status message ---
+   A reserved slot, not a block that appears: an empty message keeps its height
+   and is only invisible, so a message never moves the form or pushes the
+   buttons out of a short frame (the embedded board on lixen.com is one). Sized
+   for one line; a longer message wraps and grows the slot, which the modal's
+   own scroll absorbs. */
 .modal-message {
-    display: none;
-    margin-bottom: 1rem;
-    padding: 0.6rem 0.75rem;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    min-height: 2.3rem;
+    margin-bottom: 0.75rem;
+    padding: 0.35rem 0.75rem;
+    border: 1px solid transparent;
     border-radius: 6px;
     font-size: 0.85rem;
+    line-height: 1.3;
     text-align: center;
+    visibility: hidden;
 }
 
 .modal-message.show {
-    display: block;
+    visibility: visible;
 }
 
 .modal-message.error {
@@ -706,7 +737,8 @@ input[type="range"]::-webkit-slider-thumb {
 }
 
 /* --- Disabled state while a modal request is in flight (Issue 1) --- */
-.auth-form input:disabled {
+.auth-form input:disabled,
+.account-form input:disabled {
     opacity: 0.5;
     cursor: not-allowed;
 }
@@ -956,6 +988,37 @@ input[type="range"]:disabled {
     text-shadow: 1px 1px 2px rgba(255,255,255,0.2);
 }
 
+/* Account */
+.account-modal {
+    max-width: 360px;
+}
+
+.account-name {
+    text-align: center;
+}
+
+.danger-zone {
+    margin-top: 1.5rem;
+    padding-top: 1rem;
+    border-top: 1px solid var(--tokyo-border);
+}
+
+.danger-zone summary {
+    cursor: pointer;
+    color: var(--tokyo-red);
+    text-align: center;
+}
+
+.danger-zone p {
+    margin: 0.75rem 0 1rem;
+    font-size: 0.85rem;
+    line-height: 1.4;
+}
+
+.danger-zone .modal-buttons {
+    margin-top: 1rem;
+}
+
 /* Resign confirmation */
 .confirm-modal {
     max-width: 320px;