Port internal/xiaomi from go2rtc with stateless adaptation:
- Token passed via URL query (?token=) instead of persistent config
- tester.RegisterSource replaces streams.HandleFunc
- Stream handler extracts token from URL and populates in-memory cloud cache
- Device list endpoint embeds url-encoded token into each camera URL
- Auth flow (login/captcha/verify) unchanged from upstream
eduard256
90b3583af7