Add GitHub Actions workflow for APK/AAB builds

.github/workflows/generate-apk-aab-debug-release.yml

@@ -0,0 +1,82 @@
+name: Build APKs for PR (multi-module)
+
+# Trigger on pull requests (any branch / any PR event)
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+
+jobs:
+  build-modules:
+    name: Build ${{ matrix.module }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # Edit these module names to match your Gradle module names
+        module: [app, lyrics-maker]
+      fail-fast: false
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '17'
+
+      - name: Setup Android SDK
+        uses: android-actions/setup-android@v2
+        with:
+          api-level: 33
+          components: |
+            build-tools;33.0.2
+            platform-tools
+            platforms;android-33
+
+      - name: Cache Gradle
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle/wrapper/**') }}
+
+      - name: Ensure gradlew is executable
+        run: chmod +x ./gradlew
+
+      - name: Build APK for module ${{ matrix.module }}
+        # Using assembleRelease so you get APKs in build/outputs; if you prefer debug builds (always unsigned),
+        # change to :${{ matrix.module }}:assembleDebug
+        run: ./gradlew :modules:${{ matrix.module }}:assembleDebug --no-daemon -Porg.gradle.jvmargs=-Xmx3g
+
+      - name: Collect produced APKs
+        id: find-apks
+        run: |
+          # find APK(s) for this module (search under module build outputs)
+          APKS=( $(find . -path "./modules/${{ matrix.module }}/build/outputs/apk" -type f -name '*.apk' -print) )
+          if [ ${#APKS[@]} -eq 0 ]; then
+            echo "No APKs found for module '${{ matrix.module }}'."
+            # exit non-zero if you want the job to fail instead:
+            # exit 1
+          else
+            echo "Found APKs:"
+            for f in "${APKS[@]}"; do
+              echo " - $f"
+            done
+          fi
+          # export a newline-separated list for upload step
+          printf "%s\n" "${APKS[@]}" > apks_list.txt
+          echo "apks_list=apks_list.txt" >> $GITHUB_OUTPUT
+        shell: bash
+
+      - name: Upload APK artifact for ${{ matrix.module }}
+        if: always()     # still run to ensure artifact (even if none found, action will create empty artifact) 
+        uses: actions/upload-artifact@v4
+        with:
+          # name artifact per module so each appears separately in Actions UI
+          name: ${{ matrix.module }}-apk
+          # upload all apk files found under the module build outputs
+          path: |
+            modules/${{ matrix.module }}/build/outputs/apk/**/*.apk
+            modules/${{ matrix.module }}/build/outputs/**/**/*.apk