🔧 Under-the-Hood Improvements (Build & Size Optimization)

- Switched to NDK 27.3.13750724 for improved compatibility and simpler builds
- Reduced APK size by targeting only ARM architectures: arm64-v8a and armeabi-v7a
- OpenCV is now built with only the required modules: core and imgproc
  Unused modules like dnn, gapi, video, features2d and others are excluded

Result: Smaller APK, faster build times, and better performance on devices
