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/auth.ts

@@ -24,12 +24,19 @@ export interface AuthUser {
  * Save JWT token to localStorage
  */
 export const saveToken = (token: AuthToken): void => {
+  console.log('[Auth] saveToken called with token:', {
+    access_token: token.access_token?.substring(0, 20) + '...',
+    user_id: token.user_id,
+    username: token.username,
+    role: token.role
+  });
   localStorage.setItem(TOKEN_KEY, token.access_token);
   localStorage.setItem(USER_KEY, JSON.stringify({
     id: token.user_id,
     username: token.username,
     role: token.role
   }));
+  console.log('[Auth] Token saved to localStorage. TOKEN_KEY:', TOKEN_KEY);
 };
 
 /**