feat: Phase 28.1 — gradle wrapper + debug APK builds successfully

- gradlew + gradle-wrapper.jar (Gradle 8.11.1)
- Fixed manifest icon to @android:mipmap/sym_def_app_icon (no custom asset needed yet)
- Added adaptive icon XML + colors for future custom icon
- Removed deprecated buildfeatures.buildconfig from gradle.properties
- 17MB debug APK builds: ./gradlew assembleDebug
- local.properties auto-ignored (contains SDK path)

android/app/src/main/AndroidManifest.xml

@@ -20,7 +20,7 @@
         android:name=".YarisApp"
         android:allowBackup="false"
         android:fullBackupOnly="false"
-        android:icon="@mipmap/ic_launcher"
+        android:icon="@android:mipmap/sym_def_app_icon"
         android:label="@string/app_name"
         android:supportsRtl="true"
         android:theme="@style/Theme.YarisOBD"