feat(middleware): enhance user settings endpoint with rate limiting

- Add configured_rate_limiter import for rate limiting functionality
- Implement rate limiting in the user settings middleware chain
- Update middleware documentation to reflect new rate limiting step
- Modify _rateAndPermissionSetter function to handle rate limiting and permission setting

Author: fulleni

routes/api/v1/users/[id]/settings/_middleware.dart

@@ -1,38 +1,49 @@
 import 'package:dart_frog/dart_frog.dart';
 import 'package:flutter_news_app_api_server_full_source_code/src/middlewares/authorization_middleware.dart';
+import 'package:flutter_news_app_api_server_full_source_code/src/middlewares/configured_rate_limiter.dart';
 import 'package:flutter_news_app_api_server_full_source_code/src/middlewares/ownership_check_middleware.dart';
 import 'package:flutter_news_app_api_server_full_source_code/src/rbac/permissions.dart';
 
 /// Middleware for the user settings endpoint.
 ///
 /// This chain ensures that:
 /// 1. The user is authenticated (handled by the parent `users` middleware).
-/// 2. The correct permission (`userAppSettings...`) is required.
-/// 3. The user has that permission.
-/// 4. The user is the owner of the settings resource.
+/// 2. Rate limiting is applied.
+/// 3. The correct permission (`userAppSettings...`) is required.
+/// 4. The user has that permission.
+/// 5. The user is the owner of the settings resource.
 Handler middleware(Handler handler) {
   return handler
       // Final check: ensure the authenticated user owns this resource.
       .use(userOwnershipMiddleware())
       // Check if the user has the required permission.
       .use(authorizationMiddleware())
-      // Provide the specific permission required for this route.
-      .use(_permissionSetter());
+      // Apply rate limiting and provide the specific permission for this route.
+      .use(_rateAndPermissionSetter());
 }
 
-Middleware _permissionSetter() {
+Middleware _rateAndPermissionSetter() {
   return (handler) {
     return (context) {
       final String permission;
+      final Middleware rateLimiter;
+
       switch (context.request.method) {
         case HttpMethod.get:
           permission = Permissions.userAppSettingsReadOwned;
+          rateLimiter = createReadRateLimiter();
         case HttpMethod.put:
           permission = Permissions.userAppSettingsUpdateOwned;
+          rateLimiter = createWriteRateLimiter();
         default:
           return Response(statusCode: 405);
       }
-      return handler(context.provide<String>(() => permission));
+
+      return rateLimiter(
+        (context) => handler(
+          context.provide<String>(() => permission),
+        ),
+      )(context);
     };
   };
 }