Starter display: boundary v0 client, readout, mark button, CI

Connects to svc-gw over one WebSocket, heartbeats, treats timeout_ms of
silence as a dead link, and retries commands under the same id until acked.
Shows link state, signals with stale/null/missing told apart, the raw stream,
a mock banner on the surface, and a Mark button that stamps the recording.
Android: keeps the screen on and binds the process to the USB NCM network
when the gateway is on it. CI mirrors android-stuff's host-mode runner setup.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

README.md

@@ -19,5 +19,10 @@ assume it will always be an Android tablet.
 It is a bus subscriber like any other display: it talks to the message bus and to
 [svc-gw](gitea:yukart/svc-gw), never to hardware.
 
+```bash
+flutter test
+flutter run --dart-define=YUKART_GW=ws://<host>:7700/      # default: the car Orin, ws://192.168.55.1:7700/
+```
+
 - For implementation practice guidelines, refer to the [guidelines](docs/GUIDELINES.md);  
 - For implementation plans and history, refer to [them](docs/impl/);