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/gradle/wrapper/gradle-wrapper.properties

@@ -2,6 +2,8 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
 networkTimeout=10000
+retries=0
+retryBackOffMs=500
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists