first commit

apps/api/src/app/metrics/metrics.service.ts

@@ -0,0 +1,14 @@
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class MetricsService {
+  private readonly counters = new Map<string, number>();
+
+  increment(name: string, by = 1): void {
+    this.counters.set(name, (this.counters.get(name) ?? 0) + by);
+  }
+
+  snapshot(): Record<string, number> {
+    return Object.fromEntries(this.counters.entries());
+  }
+}