Headless K7 client

[kaybi-gh]

What problem would this solve?

K7 today expects a full UI client (Web or MAUI). Homelab and multi-room setups often need a small box or server process with no screen: kitchen speaker, NAS-side player, systemd service on Linux, or a device that only receives remote play / cast-style commands. Running a browser or MAUI shell just for playback is heavy and awkward on headless hosts.

Proposed solution

Ship a first-party headless client host that registers as a normal K7 device, connects to the server API, and handles playback without Blazor UI.

• Minimal process (CLI / systemd unit / container) with config for server URL, credentials, and output device.
• Playback path for audio (and maybe video remux to a local sink if useful), progress reporting, remote control receiver aligned with existing K7 remote play.
• Optional: expose as a target in the existing "play on device" / remote control flows so other clients can push queue to it.
• Clear scope for v1 (audio-only headless is enough to prove the model).

Alternatives considered

Use third-party OpenSubsonic clients on the headless box (works for music, not full K7 UX / remote control parity). Run Web WASM in a headless browser (fragile, wasteful).