feat(frontend): Finalize auth refactor, routing, and resolve all code review findings

frontend/src/services/api.ts

@@ -7,4 +7,18 @@ const api = axios.create({
   withCredentials: true, // Crucial for HttpOnly cookies
 })
 
+// Add a response interceptor to handle 401s
+api.interceptors.response.use(
+  (response) => response,
+  (error) => {
+    if (error.response?.status === 401) {
+      // Unauthorized - session likely expired
+      // We can't use useNavigate here as it's not a React component
+      // But we can redirect to home which will trigger the login view in App.tsx
+      window.location.href = "/"
+    }
+    return Promise.reject(error)
+  }
+)
+
 export default api