Add defensive backend URL validation and auto-cleanup

- Add getApiUrl() function to validate and clean backend URL
- Automatically strip /membership or /api suffix if present
- Log all environment variables on module load for debugging
- Add detailed URL logging in login function
- Provide fallback if REACT_APP_BACKEND_URL is undefined

This fixes the intermittent CORS error caused by incorrect backend URL

src/context/AuthContext.js

@@ -3,7 +3,34 @@ import axios from 'axios';
 
 const AuthContext = createContext();
 
-const API_URL = process.env.REACT_APP_BACKEND_URL;
+// Ensure API_URL is correctly set, with fallback and validation
+const getApiUrl = () => {
+  const url = process.env.REACT_APP_BACKEND_URL;
+
+  // Log the environment variable for debugging
+  console.log('[AuthContext] Environment check:', {
+    REACT_APP_BACKEND_URL: url,
+    REACT_APP_BASENAME: process.env.REACT_APP_BASENAME,
+    PUBLIC_URL: process.env.PUBLIC_URL
+  });
+
+  if (!url) {
+    console.error('[AuthContext] REACT_APP_BACKEND_URL is not defined!');
+    // Fallback to current origin API (same domain)
+    return window.location.origin.replace('/membership', '');
+  }
+
+  // Remove any trailing /membership or /api from the backend URL
+  const cleanUrl = url.replace(/\/(membership|api)\/?$/, '');
+
+  if (cleanUrl !== url) {
+    console.warn('[AuthContext] Cleaned backend URL:', { original: url, cleaned: cleanUrl });
+  }
+
+  return cleanUrl;
+};
+
+const API_URL = getApiUrl();
 
 export const AuthProvider = ({ children }) => {
   const [user, setUser] = useState(null);
@@ -55,7 +82,11 @@ export const AuthProvider = ({ children }) => {
 
   const login = async (email, password) => {
     try {
-      console.log('[AuthContext] Starting login request...');
+      console.log('[AuthContext] Starting login request...', {
+        API_URL: API_URL,
+        envBackendUrl: process.env.REACT_APP_BACKEND_URL,
+        fullUrl: `${API_URL}/api/auth/login`
+      });
 
       const response = await axios.post(
         `${API_URL}/api/auth/login`,