Phase 2.3: JWT Authentication implementation

- Implemented JWT-based authentication system with access and refresh tokens
- Added password hashing service using PBKDF2
- Created authentication handlers: register, login, refresh, logout
- Added protected routes with JWT middleware
- Created user profile handlers
- Fixed all compilation errors
- Added integration tests for authentication endpoints
- Added reqwest dependency for testing
- Created test script and environment example documentation

All changes:
- backend/src/auth/: Complete auth module (JWT, password, claims)
- backend/src/handlers/: Auth, users, and health handlers
- backend/src/middleware/: JWT authentication middleware
- backend/src/config/: Added AppState with Clone derive
- backend/src/main.rs: Fixed imports and added auth routes
- backend/src/db/mod.rs: Changed error handling to anyhow::Result
- backend/Cargo.toml: Added reqwest for testing
- backend/tests/auth_tests.rs: Integration tests
- thoughts/: Documentation updates (STATUS.md, env.example, test_auth.sh)

backend/Cargo.toml

@@ -27,3 +27,4 @@ thiserror = "1"
 
 [dev-dependencies]
 tokio-test = "0.4"
+reqwest = { version = "0.12", features = ["json"] }