feat(monitoring): observability stack + app instrumentation

- /health/ready (DB+MinIO+Casdoor checks, webhook post-deploy gate),
  /metrics via prometheus-fastapi-instrumentator, Sentry/GlitchTip capture,
  X-Request-ID middleware + JSON access logging (PROCUREMENT_LOG_FORMAT)
- server-side analytics (OpenPanel Track API): login, quote lifecycle,
  receipts — fire-and-forget, disabled without env config
- monitoring/ compose project: GlitchTip(+pg), Prometheus(+alerts),
  Grafana(provisioned ERP dashboard), Loki+Promtail, node/postgres
  exporters, cAdvisor — mem-limited (~2.2GB), loopback admin UIs,
  separate from app deploys; erp_shared network for scraping
- frontend: @openpanel/web + @sentry/react (build-arg gated, no-op when
  unset), funnel events (login, wizard steps, quote submitted)
- compose: api healthcheck, observability env wiring, .env.example keys

docker-compose.yml

@@ -13,6 +13,10 @@ services:
     ports:
       - "5433:5432"
 
+    networks:
+      - default
+      - shared # monitoring stack scrapes it (postgres-exporter)
+
     volumes:
       - postgres_data:/var/lib/postgresql
       - ./sql/migration.sql:/docker-entrypoint-initdb.d/01-migration.sql:ro
@@ -196,10 +200,28 @@ services:
       # Console admin used by POST /users/sync (identity mirroring).
       PROCUREMENT_CASDOOR_ADMIN_USER: admin
       PROCUREMENT_CASDOOR_ADMIN_PASSWORD: ${CASDOOR_ADMIN_PASSWORD:-123}
+      # Observability (Phase 2) — see monitoring/README.md
+      PROCUREMENT_LOG_FORMAT: ${LOG_FORMAT:-text}
+      PROCUREMENT_SENTRY_DSN: ${SENTRY_DSN_BACKEND:-}
+      PROCUREMENT_OPENPANEL_API_URL: ${OPENPANEL_API_URL:-}
+      PROCUREMENT_OPENPANEL_CLIENT_ID: ${OPENPANEL_CLIENT_ID:-}
+      PROCUREMENT_OPENPANEL_CLIENT_SECRET: ${OPENPANEL_CLIENT_SECRET:-}
 
     ports:
       - "8000:8000"
 
+    networks:
+      - traefik_network
+      - default
+      - shared # monitoring stack scrapes api:8000/metrics
+
+    healthcheck:
+      test: ["CMD-SHELL", "python -c \"import urllib.request as u; u.urlopen('http://127.0.0.1:8000/health', timeout=3)\""]
+      interval: 30s
+      timeout: 5s
+      retries: 5
+      start_period: 40s
+
     labels:
       - traefik.enable=true
       - traefik.http.routers.api.rule=Host(`${API_HOST:-api.localhost}`)
@@ -225,6 +247,10 @@ services:
         # Developer Mode panel on the login page — dev-only aid. Production
         # builds MUST leave this false (identity comes from Casdoor tokens).
         DEV_LOGIN_ENABLED: ${DEV_LOGIN_ENABLED:-false}
+        # Observability (build-time baked; empty = disabled)
+        VITE_OPENPANEL_URL: ${OPENPANEL_PUBLIC_URL:-}
+        VITE_OPENPANEL_CLIENT_ID: ${OPENPANEL_CLIENT_ID:-}
+        VITE_SENTRY_DSN: ${SENTRY_DSN_FRONTEND:-}
     container_name: procurement-frontend
 
     labels:
@@ -248,6 +274,11 @@ networks:
   traefik_network:
     name: traefik_network
     driver: bridge
+  # Fixed-name network shared with the monitoring stack (monitoring compose
+  # joins it as external) — carries /metrics scrapes and postgres-exporter.
+  shared:
+    name: erp_shared
+    driver: bridge
 
 volumes:
   postgres_data: