perf(android): reduce APK size with ABI splitting, R8, and lib exclusions (#2)

- Split release APK per ABI (arm64 + x64 only), dropping universal fat build
- Enable R8 minification and resource shrinking for release builds
- Exclude Vulkan debug validation layer from release packaging
- Exclude unused MediaPipe image generation libs from release packaging

Author: priyavratuniyal

.github/workflows/release.yml

@@ -35,18 +35,20 @@ jobs:
         run: dart run build_runner build --delete-conflicting-outputs
 
       - name: Build release APK
-        run: flutter build apk --release
+        run: flutter build apk --release --split-per-abi --target-platform android-arm64,android-x64
 
-      - name: Rename APK with version
+      - name: Rename APKs with version
         run: |
-          mv build/app/outputs/flutter-apk/app-release.apk \
-             build/app/outputs/flutter-apk/koshika-${{ github.ref_name }}.apk
+          cd build/app/outputs/flutter-apk
+          for apk in app-*-release.apk; do
+            mv "$apk" "koshika-${{ github.ref_name }}-${apk#app-}"
+          done
 
       - name: Create GitHub Release
         uses: softprops/action-gh-release@v2
         with:
           name: ${{ github.ref_name }}
-          files: build/app/outputs/flutter-apk/koshika-${{ github.ref_name }}.apk
+          files: build/app/outputs/flutter-apk/koshika-${{ github.ref_name }}-*.apk
           generate_release_notes: true
           draft: false
           prerelease: ${{ contains(github.ref_name, '-') }}

android/app/build.gradle.kts

@@ -35,9 +35,19 @@ android {
             // TODO: Add your own signing config for the release build.
             // Signing with the debug keys for now, so `flutter run --release` works.
             signingConfig = signingConfigs.getByName("debug")
+            isMinifyEnabled = true
+            isShrinkResources = true
             proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
         }
     }
+
+    packaging {
+        jniLibs {
+            excludes += "**/libVkLayer_khronos_validation.so"
+            excludes += "**/libmediapipe_tasks_vision_image_generator_jni.so"
+            excludes += "**/libimagegenerator_gpu.so"
+        }
+    }
 }
 
 flutter {