feat: migrate to Capacitor wrapper for fully-offline Android

Replace the native Kotlin/Compose port with a Capacitor 8 wrapper around
the upstream loto SvelteKit PWA. Loto is consumed as a git submodule and
its static build is bundled into the APK at sync time. The wrapper has
no INTERNET permission, so fully offline is enforced rather than
conventional.

- loto/ submodule pinned to dfb1c1e
- android/ scaffolded by cap add android; signing wired via env vars
- All 184 voice MP3s + service worker bundled in assets/public/
- CI checkouts submodule, runs npm build, then Gradle inside android/
- Native port preserved in git history at fe52232 and 9a35686

.github/workflows/build-debug.yml

@@ -11,6 +11,13 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up Node 20
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
 
       - name: Set up JDK 17
         uses: actions/setup-java@v4
@@ -21,12 +28,19 @@ jobs:
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v3
 
-      - name: Lint + unit tests + assemble debug
-        run: ./gradlew lint test :app:assembleDebug
+      - name: Install wrapper deps
+        run: npm ci
+
+      - name: Build loto + sync into Android
+        run: npm run build
+
+      - name: Assemble debug APK
+        working-directory: android
+        run: ./gradlew :app:assembleDebug
 
       - name: Upload debug APK
         uses: actions/upload-artifact@v4
         with:
           name: debug-apk
-          path: app/build/outputs/apk/debug/*.apk
+          path: android/app/build/outputs/apk/debug/*.apk
           retention-days: 7