feat: Enhance login error reporting with backend pre-validation and update signup to require email verification instead of auto-login.

src/app/login/page.tsx

@@ -18,19 +18,41 @@ export default function LoginPage() {
     setLoading(true);
     setError('');
 
-    const result = await signIn('credentials', {
-      email,
-      password,
-      redirect: false,
-    });
+    try {
+      // First, validate credentials with backend to get proper error messages
+      const validateRes = await fetch(`${process.env.NEXT_PUBLIC_API_URL}/auth/login`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ email, password }),
+      });
 
-    setLoading(false);
+      const validateData = await validateRes.json();
 
-    if (result?.error) {
-      setError('Invalid email or password');
-    } else {
-      router.push('/');
-      router.refresh();
+      if (!validateRes.ok) {
+        // Show the actual error message from backend
+        setError(validateData.message || 'Invalid email or password');
+        setLoading(false);
+        return;
+      }
+
+      // If validation passed, use NextAuth to create session
+      const result = await signIn('credentials', {
+        email,
+        password,
+        redirect: false,
+      });
+
+      setLoading(false);
+
+      if (result?.error) {
+        setError('Login failed. Please try again.');
+      } else {
+        router.push('/');
+        router.refresh();
+      }
+    } catch (err) {
+      setLoading(false);
+      setError('An error occurred. Please try again.');
     }
   };