Initial scaffold: FastAPI backend + Vue 3 frontend + Docker setup

Backend: config/db/security/logging core, SQLAlchemy models (Server,
Credential, UpdateJob, UpdateLog, AuditLog, User), services (winrm, ssh,
cau, audit, job_runner), REST API (auth, servers, updates, audit),
Socket.io WebSocket layer.
Frontend: Vue 3 + TS + Pinia + Tailwind, Views (Dashboard, Servers,
Updates, Audit, Login), axios + socket.io-client, nginx prod config.

backend/README.md

@@ -0,0 +1,12 @@
+# Insight Updater Backend
+
+FastAPI backend for server update orchestration (WinRM/SSH/CAU) with WebSocket live logs.
+
+## Development
+
+```bash
+pip install -e ".[dev]"
+uvicorn app.main:app --reload
+```
+
+API docs: http://localhost:8000/docs