fix: include native module sources in git tracking

Fix .gitignore to only exclude root android/ and ios/
(Expo prebuild output) while keeping modules/ native code.
Add Android WallpaperService Kotlin sources, GLSL shaders,
manifest, and Gradle config.

.gitignore

@@ -1,7 +1,7 @@
 node_modules/
 .expo/
-android/
-ios/
+/android/
+/ios/
 dist/
 .env
 *.jks