isTauri: boolean = ...

Base HTTP client. In Tauri the backend runs at http://127.0.0.1:{port}; in browser dev Vite proxies /api → http://127.0.0.1:8000, so we use an empty base URL and let the proxy handle it.

In Tauri, main.tsx resolves the actual API port via the get_api_port command at startup and calls setApiPort() before React mounts.