Add v9.0: Auto-update system with Gitea integration

- Implement UpdateManager to check Gitea releases for new versions
- Add update dialogs with mandatory/optional update support
- Integrate DownloadManager for APK downloads
- Add FileProvider configuration for app installation
- Support update-manifest.json for version control enforcement
- Add comprehensive update strings and error handling
- Include gradlew executable permissions

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/build.gradle

@@ -8,8 +8,8 @@ android {
         applicationId "com.streamplayer"
         minSdk 21
         targetSdk 33
-        versionCode 1
-        versionName "1.0"
+        versionCode 90000
+        versionName "9.0.0"
     }
 
     buildTypes {
@@ -30,6 +30,10 @@ android {
         abortOnError = false
     }
 
+    buildFeatures {
+        buildConfig = true
+    }
+
     packaging {
         resources {
             excludes += 'META-INF/com.android.tools/proguard/coroutines.pro'