fix: Auto-update APK install via FileProvider + dynamic version

- Native ApkInstallerModule: FileProvider content:// URI for Android 7+
- REQUEST_INSTALL_PACKAGES permission in AndroidManifest
- file_paths.xml for FileProvider cache access
- APP_VERSION reads from package.json (not hardcoded)
- "Auf Updates pruefen" button in Settings
- Version display reads from package.json dynamically

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

android/android/app/src/main/java/com/ariacockpit/MainApplication.kt

@@ -18,8 +18,7 @@ class MainApplication : Application(), ReactApplication {
       object : DefaultReactNativeHost(this) {
         override fun getPackages(): List<ReactPackage> =
             PackageList(this).packages.apply {
-              // Packages that cannot be autolinked yet can be added manually here, for example:
-              // add(MyReactNativePackage())
+              add(ApkInstallerPackage())
             }
 
         override fun getJSMainModuleName(): String = "index"