feat(metrics): add MetricsService, HttpMetricsInterceptor, and metric constants

- Extract metric names into constants with goodgo_ prefix for business metrics
- Add MetricsService for type-safe metric recording
- Add HttpMetricsInterceptor for automatic request duration/count tracking
- Register interceptor globally via APP_INTERCEPTOR
- Include linter auto-fixes for test files

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/app.module.ts

@@ -1,5 +1,5 @@
 import { type MiddlewareConsumer, Module, type NestModule } from '@nestjs/common';
-import { APP_FILTER, APP_GUARD } from '@nestjs/core';
+import { APP_FILTER, APP_GUARD, APP_INTERCEPTOR } from '@nestjs/core';
 import { CqrsModule } from '@nestjs/cqrs';
 import { ThrottlerModule } from '@nestjs/throttler';
 import { SentryGlobalFilter, SentryModule } from '@sentry/nestjs/setup';
@@ -8,7 +8,7 @@ import { AnalyticsModule } from '@modules/analytics';
 import { AuthModule } from '@modules/auth';
 import { ListingsModule } from '@modules/listings';
 import { McpIntegrationModule } from '@modules/mcp';
-import { MetricsModule } from '@modules/metrics';
+import { HttpMetricsInterceptor, MetricsModule } from '@modules/metrics';
 import { NotificationsModule } from '@modules/notifications';
 import { PaymentsModule } from '@modules/payments';
 import { SearchModule } from '@modules/search';
@@ -68,6 +68,10 @@ import { AppController } from './app.controller';
       provide: APP_GUARD,
       useClass: ThrottlerBehindProxyGuard,
     },
+    {
+      provide: APP_INTERCEPTOR,
+      useClass: HttpMetricsInterceptor,
+    },
   ],
 })
 export class AppModule implements NestModule {