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

.gitea/workflows/ci.yaml

@@ -0,0 +1,63 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+    paths:
+      - 'lib/**'
+      - 'test/**'
+      - 'android/**'
+      - 'pubspec.yaml'
+      - 'pubspec.lock'
+      - '.gitea/workflows/**'
+  pull_request:
+    branches: [ master ]
+  workflow_dispatch:
+
+# Same self-hosted runner shape as android-stuff (halogen, host mode, label
+# flutter-android): the toolchain on the host is the one that verified the
+# release, and nothing installs per run. Host mode is also what keeps Gradle and
+# pub caches warm between runs.
+
+jobs:
+  analyze:
+    name: Analyze & Test
+    runs-on: flutter-android
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Toolchain
+        run: |
+          flutter --version
+          echo "ANDROID_HOME=${ANDROID_HOME:?not set on this runner}"
+          flutter-android-preflight .
+
+      - name: Get dependencies
+        run: flutter pub get
+
+      - name: Analyze
+        run: flutter analyze
+
+      - name: Test
+        run: flutter test
+
+  apk:
+    name: Debug APK
+    runs-on: flutter-android
+    needs: [analyze]
+    if: github.event_name == 'push' || github.event_name == 'workflow_dispatch'
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Get dependencies
+        run: flutter pub get
+
+      # Debug-signed: this is a side-loaded in-car display, not a store release.
+      - name: Build APK
+        run: flutter build apk --debug
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: yukart-display-debug-apk
+          path: build/app/outputs/flutter-apk/app-debug.apk
+          if-no-files-found: error