feat: CMDB full-stack app - FastAPI + PostgreSQL + React

- PostgreSQL schema: 14 tables, JSONB attributes, audit triggers, soft delete
- FastAPI backend: CRUD, search/filter, relationship graph, bulk import, JWT RBAC
- React frontend: CI table, detail card, force-graph, dashboard
- Seed data: homelab scenario (Proxmox, Mikrotik, VMs, services)
- Docker Compose + Kubernetes manifests
- 20 backend tests (pytest + httpx)

backend/.env.example

@@ -0,0 +1,8 @@
+# ============================================================
+# Environment variables for backend
+# ============================================================
+DATABASE_URL=postgresql+asyncpg://cmdb:cmdb_secret@localhost:5432/cmdb
+JWT_SECRET=CHANGE_ME_IN_PRODUCTION
+CORS_ORIGINS=["http://localhost:3000","http://localhost:5173"]
+RATE_LIMIT_PER_MINUTE=120
+DEBUG=false