feat: upgrade next-auth to v5.0.0-beta.29 and refactor authentication middleware

- Updated next-auth dependency in package.json to version 5.0.0-beta.29.
- Refactored create-admin script to use a valid email format.
- Implemented authentication middleware for various API routes to enforce access control.
- Refactored API route handlers to improve readability and maintainability.
- Enhanced error handling in authentication error page.
- Added detailed tests for authentication flow, including protected routes and NextAuth endpoints.

src/app/auth/error/page.js

@@ -1,4 +1,24 @@
+'use client'
+
+import { useSearchParams } from 'next/navigation'
+
 export default function AuthError() {
+  const searchParams = useSearchParams()
+  const error = searchParams.get('error')
+  
+  const getErrorMessage = (error) => {
+    switch (error) {
+      case 'CredentialsSignin':
+        return 'Invalid email or password. Please check your credentials and try again.'
+      case 'AccessDenied':
+        return 'Access denied. You do not have permission to sign in.'
+      case 'Verification':
+        return 'The verification token has expired or has already been used.'
+      default:
+        return 'An unexpected error occurred during authentication. Please try again.'
+    }
+  }
+
   return (
     <div className="min-h-screen flex items-center justify-center bg-gray-50 py-12 px-4 sm:px-6 lg:px-8">
       <div className="max-w-md w-full space-y-8">
@@ -7,8 +27,13 @@ export default function AuthError() {
             Authentication Error
           </h2>
           <p className="mt-2 text-sm text-gray-600">
-            There was a problem signing you in. Please try again.
+            {getErrorMessage(error)}
           </p>
+          {error && (
+            <p className="mt-1 text-xs text-gray-500">
+              Error code: {error}
+            </p>
+          )}
           <div className="mt-6">
             <a
               href="/auth/signin"