v0.2.0 restructured and generalized to be more modular, added golang-jwt dependency

doc.go

@@ -0,0 +1,53 @@
+// FILE: auth/doc.go
+package auth
+
+/*
+Package auth provides modular authentication components:
+
+# Argon2 Password Hashing
+
+Standalone password hashing using Argon2id:
+
+	hash, err := auth.HashPassword("password123")
+	err = auth.VerifyPassword("password123", hash)
+
+	// With custom parameters
+	hash, err := auth.HashPassword("password123",
+		auth.WithTime(5),
+		auth.WithMemory(128*1024))
+
+# JWT Token Management
+
+JSON Web Token generation and validation:
+
+	// HS256 (symmetric)
+	jwtMgr, _ := auth.NewJWT(secret)
+	token, _ := jwtMgr.GenerateToken("user1", claims)
+	userID, claims, _ := jwtMgr.ValidateToken(token)
+
+	// RS256 (asymmetric)
+	jwtMgr, _ := auth.NewJWTRSA(privateKey)
+
+	// One-off operations
+	token, _ := auth.GenerateHS256Token(secret, "user1", claims, 1*time.Hour)
+
+# SCRAM-SHA256 Authentication
+
+Server and client implementation for SCRAM:
+
+	// Server
+	server := auth.NewScramServer()
+	server.AddCredential(credential)
+
+	// Client
+	client := auth.NewScramClient(username, password)
+
+# HTTP Authentication Parsing
+
+Utility functions for HTTP headers:
+
+	username, password, _ := auth.ParseBasicAuth(header)
+	token, _ := auth.ParseBearerToken(header)
+
+Each module can be used independently without initializing other components.
+*/