feat: better rate limit errors

backend/src/server/plugins/error-handler.ts

@@ -10,6 +10,7 @@ import {
   GatewayTimeoutError,
   InternalServerError,
   NotFoundError,
+  RateLimitError,
   ScimRequestError,
   UnauthorizedError
 } from "@app/lib/errors";
@@ -27,7 +28,8 @@ enum HttpStatusCodes {
   Forbidden = 403,
   // eslint-disable-next-line @typescript-eslint/no-shadow
   InternalServerError = 500,
-  GatewayTimeout = 504
+  GatewayTimeout = 504,
+  RateLimitExceeded = 429
 }
 
 export const fastifyErrHandler = fastifyPlugin(async (server: FastifyZodProvider) => {
@@ -69,6 +71,12 @@ export const fastifyErrHandler = fastifyPlugin(async (server: FastifyZodProvider
         message: error.message,
         error: error.name
       });
+    } else if (error instanceof RateLimitError) {
+      void res.status(HttpStatusCodes.RateLimitExceeded).send({
+        statusCode: HttpStatusCodes.RateLimitExceeded,
+        message: error.message,
+        error: error.name
+      });
     } else if (error instanceof ScimRequestError) {
       void res.status(error.status).send({
         schemas: error.schemas,