fix(auth): sanitize error messages in error page

Add basic XSS sanitization by removing angle brackets from error
URL parameters before rendering.

src/app/auth/error/page.tsx

@@ -10,8 +10,13 @@ function Search() {
   const searchParams = useSearchParams()
   const errorMessage = searchParams.get('error')
   
+  // Sanitize error message to prevent XSS
+  const sanitizedError = errorMessage 
+    ? errorMessage.replace(/[<>]/g, '') 
+    : 'An authentication error occurred'
+
   return (<div className="text-center p-3 bg-background rounded-lg">
-    {errorMessage}
+    {sanitizedError}
   </div>)
 }