refactor: centralize domain values and enforce numeric lint

src/common/decorators/api-safe-error-response.decorator.ts

@@ -1,4 +1,4 @@
-import { applyDecorators } from '@nestjs/common';
+import { HttpStatus, applyDecorators } from '@nestjs/common';
 import {
   ApiExtraModels,
   ApiProperty,
@@ -35,10 +35,13 @@ function problemResponse(status: number, description: string) {
 export function ApiProblemResponses(): MethodDecorator & ClassDecorator {
   return applyDecorators(
     ApiExtraModels(ProblemDetailsDto),
-    problemResponse(400, 'Invalid request'),
-    problemResponse(401, 'Authentication required'),
-    problemResponse(404, 'Resource not found'),
-    problemResponse(503, 'Upstream service unavailable'),
-    problemResponse(500, 'Internal server error'),
+    problemResponse(HttpStatus.BAD_REQUEST, 'Invalid request'),
+    problemResponse(HttpStatus.UNAUTHORIZED, 'Authentication required'),
+    problemResponse(HttpStatus.NOT_FOUND, 'Resource not found'),
+    problemResponse(
+      HttpStatus.SERVICE_UNAVAILABLE,
+      'Upstream service unavailable',
+    ),
+    problemResponse(HttpStatus.INTERNAL_SERVER_ERROR, 'Internal server error'),
   );
 }