- manage.sh: dev command starts uvicorn --reload on :8503 and Vite dev
server (auto-port from 5173); kills API on EXIT/INT/TERM trap
- manage.sh: ENV_UI defaults to 'cf' env (overridable via AVOCET_ENV)
- vite.config.ts: add server.proxy to forward /api to :8503 so Vite
dev server can reach the backend without CORS issues