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/src/middleware/auth.rs

@@ -0,0 +1,51 @@
+use axum::{
+    extract::{Request, State},
+    http::StatusCode,
+    middleware::Next,
+    response::Response,
+};
+use crate::auth::claims::AccessClaims;
+use crate::config::AppState;
+
+pub async fn jwt_auth_middleware(
+    State(state): State<AppState>,
+    mut req: Request,
+    next: Next,
+) -> Result<Response, StatusCode> {
+    let headers = req.headers();
+    
+    // Extract Authorization header
+    let auth_header = headers
+        .get("Authorization")
+        .and_then(|h| h.to_str().ok())
+        .ok_or(StatusCode::UNAUTHORIZED)?;
+    
+    // Check Bearer token format
+    if !auth_header.starts_with("Bearer ") {
+        return Err(StatusCode::UNAUTHORIZED);
+    }
+    
+    let token = &auth_header[7..]; // Remove "Bearer " prefix
+    
+    // Verify token
+    let claims = state
+        .jwt_service
+        .verify_access_token(token)
+        .map_err(|_| StatusCode::UNAUTHORIZED)?;
+    
+    // Add claims to request extensions for handlers to use
+    req.extensions_mut().insert(claims);
+    
+    Ok(next.run(req).await)
+}
+
+// Extension method to extract claims from request
+pub trait RequestClaimsExt {
+    fn claims(&self) -> Option<&AccessClaims>;
+}
+
+impl RequestClaimsExt for Request {
+    fn claims(&self) -> Option<&AccessClaims> {
+        self.extensions().get::<AccessClaims>()
+    }
+}