debug: add console logging to token save and request interceptor

- Log when saveToken is called with token details
- Log when request interceptor checks for token
- Log when Authorization header is set or token is missing
- Helps diagnose 401 Unauthorized issues after login

frontend/lib/api.ts

@@ -27,8 +27,12 @@ const axiosInstance = axios.create({
 
 axiosInstance.interceptors.request.use((config) => {
   const token = getToken();
+  console.log('[API] Request interceptor - token exists:', !!token, 'URL:', config.url);
   if (token) {
     config.headers.Authorization = `Bearer ${token}`;
+    console.log('[API] Authorization header set');
+  } else {
+    console.warn('[API] No token found in localStorage');
   }
   return config;
 }, (error) => Promise.reject(error));