feat(phase-4): WS4 — Agent Marketplace (public registry, pagination, filters)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/metrics/registry.ts

@@ -147,3 +147,15 @@ export const dbPoolWaitingRequests = new Gauge({
   help: 'Current number of requests waiting for a PostgreSQL connection.',
   registers: [metricsRegistry],
 });
+
+/**
+ * Total number of authenticated API calls per tenant.
+ * Incremented on every request that passes auth middleware successfully.
+ * Labels: tenant_id (organization_id from the JWT payload)
+ */
+export const tenantApiCallsTotal = new Counter({
+  name: 'agentidp_tenant_api_calls_total',
+  help: 'Total number of authenticated API calls, labeled by tenant.',
+  labelNames: ['tenant_id'] as const,
+  registers: [metricsRegistry],
+});