feat(phase-2): workstream 7 — Prometheus + Grafana Monitoring

- Add prom-client 15; shared registry in src/metrics/registry.ts (7 metrics)
- HTTP request counter + duration histogram via metricsMiddleware
- DB query duration histogram wrapping pg Pool.query
- Redis command duration histogram via typed instrumentRedisMethod wrapper
- agentidp_tokens_issued_total in OAuth2Service
- agentidp_agents_registered_total in AgentService
- GET /metrics unauthenticated endpoint (Prometheus text format)
- docker-compose.monitoring.yml overlay (Prometheus + Grafana)
- Grafana auto-provisioned datasource + pre-built AgentIdP dashboard
- docs/devops/operations.md monitoring section added
- 36/36 unit tests passing, 100% coverage on new metrics code
- Fix pre-existing unused import in tests/integration/agents.test.ts

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

package-lock.json

@@ -8,6 +8,7 @@
       "name": "sentryagent-idp",
       "version": "1.0.0",
       "dependencies": {
+        "@open-policy-agent/opa-wasm": "^1.10.0",
         "bcryptjs": "^2.4.3",
         "cors": "^2.8.5",
         "dotenv": "^16.4.5",
@@ -20,6 +21,7 @@
         "pg": "^8.11.3",
         "pino": "^8.19.0",
         "pino-http": "^9.0.0",
+        "prom-client": "^15.1.3",
         "redis": "^4.6.13",
         "uuid": "^9.0.1"
       },
@@ -1263,6 +1265,31 @@
         "node": ">= 8"
       }
     },
+    "node_modules/@open-policy-agent/opa-wasm": {
+      "version": "1.10.0",
+      "resolved": "https://registry.npmjs.org/@open-policy-agent/opa-wasm/-/opa-wasm-1.10.0.tgz",
+      "integrity": "sha512-ymR/nFS3nO9o24j9xowGGQaf+Gmb813QcxUpVZkfRlJkawKWqSIllnEH15agyWjijmOIyhA+OBErenx6N3jphw==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "sprintf-js": "^1.1.2",
+        "yaml": "^1.10.2"
+      }
+    },
+    "node_modules/@open-policy-agent/opa-wasm/node_modules/sprintf-js": {
+      "version": "1.1.3",
+      "resolved": "https://registry.npmjs.org/sprintf-js/-/sprintf-js-1.1.3.tgz",
+      "integrity": "sha512-Oo+0REFV59/rz3gfJNKQiBlwfHaSESl1pcGyABQsnnIfWOFt6JNj5gCog2U6MLZ//IGYD+nA8nI+mTShREReaA==",
+      "license": "BSD-3-Clause"
+    },
+    "node_modules/@opentelemetry/api": {
+      "version": "1.9.1",
+      "resolved": "https://registry.npmjs.org/@opentelemetry/api/-/api-1.9.1.tgz",
+      "integrity": "sha512-gLyJlPHPZYdAk1JENA9LeHejZe1Ti77/pTeFm/nMXmQH/HFZlcS/O2XJB+L8fkbrNSqhdtlvjBVjxwUYanNH5Q==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=8.0.0"
+      }
+    },
     "node_modules/@paralleldrive/cuid2": {
       "version": "2.3.1",
       "resolved": "https://registry.npmjs.org/@paralleldrive/cuid2/-/cuid2-2.3.1.tgz",
@@ -2414,6 +2441,12 @@
       "integrity": "sha512-V/Hy/X9Vt7f3BbPJEi8BdVFMByHi+jNXrYkW3huaybV/kQ0KJg0Y6PkEMbn+zeT+i+SiKZ/HMqJGIIt4LZDqNQ==",
       "license": "MIT"
     },
+    "node_modules/bintrees": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/bintrees/-/bintrees-1.0.2.tgz",
+      "integrity": "sha512-VOMgTMwjAaUG580SXn3LacVgjurrbMme7ZZNYGSSV7mmtY6QQRh0Eg3pwIcntQ77DErK1L0NxkbetjcoXzVwKw==",
+      "license": "MIT"
+    },
     "node_modules/body-parser": {
       "version": "1.20.4",
       "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.20.4.tgz",
@@ -6164,6 +6197,19 @@
       "integrity": "sha512-mqn0kFRl0EoqhnL0GQ0veqFHyIN1yig9RHh/InzORTUiZHFRAur+aMtRkELNwGs9aNwKS6tg/An4NYBPGwvtzQ==",
       "license": "MIT"
     },
+    "node_modules/prom-client": {
+      "version": "15.1.3",
+      "resolved": "https://registry.npmjs.org/prom-client/-/prom-client-15.1.3.tgz",
+      "integrity": "sha512-6ZiOBfCywsD4k1BN9IX0uZhF+tJkV8q8llP64G5Hajs4JOeVLPCwpPVcpXy3BwYiUGgyJzsJJQeOIv7+hDSq8g==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@opentelemetry/api": "^1.4.0",
+        "tdigest": "^0.1.1"
+      },
+      "engines": {
+        "node": "^16 || ^18 || >=20"
+      }
+    },
     "node_modules/prompts": {
       "version": "2.4.2",
       "resolved": "https://registry.npmjs.org/prompts/-/prompts-2.4.2.tgz",
@@ -6933,6 +6979,15 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/tdigest": {
+      "version": "0.1.2",
+      "resolved": "https://registry.npmjs.org/tdigest/-/tdigest-0.1.2.tgz",
+      "integrity": "sha512-+G0LLgjjo9BZX2MfdvPfH+MKLCrxlXSYec5DaPYP1fe6Iyhf0/fSmJ0bFiZ1F8BT6cGXl2LpltQptzjXKWEkKA==",
+      "license": "MIT",
+      "dependencies": {
+        "bintrees": "1.0.2"
+      }
+    },
     "node_modules/test-exclude": {
       "version": "6.0.0",
       "resolved": "https://registry.npmjs.org/test-exclude/-/test-exclude-6.0.0.tgz",
@@ -7453,6 +7508,15 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/yaml": {
+      "version": "1.10.3",
+      "resolved": "https://registry.npmjs.org/yaml/-/yaml-1.10.3.tgz",
+      "integrity": "sha512-vIYeF1u3CjlhAFekPPAk2h/Kv4T3mAkMox5OymRiJQB0spDP10LHvt+K7G9Ny6NuuMAb25/6n1qyUjAcGNf/AA==",
+      "license": "ISC",
+      "engines": {
+        "node": ">= 6"
+      }
+    },
     "node_modules/yargs": {
       "version": "17.7.2",
       "resolved": "https://registry.npmjs.org/yargs/-/yargs-17.7.2.tgz",