fix(auth): display detailed validation error messages from backend

- Extract validation error details from backend response
- Show specific error messages instead of generic 'Validation Error'
- Join multiple validation errors with commas for better UX
- Improves password validation error display for users

frontend/src/contexts/AuthContext.jsx

@@ -56,6 +56,11 @@ export const AuthProvider = ({ children }) => {
       localStorage.setItem('user', JSON.stringify(userData));
       return userData;
     } catch (error) {
+      // Handle validation errors with details
+      if (error.data?.details && Array.isArray(error.data.details)) {
+        const errorMessages = error.data.details.map(detail => detail.msg).join(', ');
+        throw new Error(errorMessages);
+      }
       throw new Error(error.data?.error || 'Registration failed');
     }
   };