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

frontend/src/vite-env.d.ts

@@ -1 +1,10 @@
 /// <reference types="vite/client" />
+
+// Observability build-time configuration (empty = feature disabled)
+interface ImportMetaEnv {
+  readonly VITE_OPENPANEL_URL?: string;
+  readonly VITE_OPENPANEL_CLIENT_ID?: string;
+  readonly VITE_SENTRY_DSN?: string;
+  readonly VITE_ENABLE_DEV_LOGIN?: string;
+  readonly VITE_API_BASE_URL?: string;
+}