App 2.19.2: Full screen for CarPlay (experiment)

Adds com.allgo.carplay.service to immersive.full in Android 9's
policy_control setting when switched on, removes only that entry when
off. Car build (system user) only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

app/build.gradle

@@ -34,8 +34,8 @@ android {
         applicationId "com.stinnesbeck.nilsmg4"
         minSdk 27
         targetSdk 36
-        versionCode 100
-        versionName "2.19.1"
+        versionCode 101
+        versionName "2.19.2"
 
         // Nothing about the server ships in the APK: its URL and ingest token are entered in
         // the app's Server tab (ServerConfig), and the database is only reachable by the server.