ci: add GitHub Actions workflow for debug/release APK builds and tagged releases

Author: Milkii Brewster

.github/workflows/build.yml

@@ -0,0 +1,90 @@
+name: Build & Release
+
+on:
+  push:
+    branches: [ master ]
+    tags:
+      - 'v*'
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    name: Build APKs
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+          cache: gradle
+
+      - name: Set up Android SDK
+        uses: android-actions/setup-android@v3
+
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+
+      - name: Build debug APK
+        run: ./gradlew assembleDebug
+
+      - name: Build release APK
+        run: ./gradlew assembleRelease
+        # Note: release APK will be unsigned without signing config.
+        # Add KEYSTORE secrets and a signingConfigs block in build.gradle to sign.
+
+      - name: Upload debug APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: app-debug
+          path: app/build/outputs/apk/debug/app-debug.apk
+          retention-days: 14
+
+      - name: Upload release APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: app-release-unsigned
+          path: app/build/outputs/apk/release/app-release-unsigned.apk
+          retention-days: 14
+
+  release:
+    name: Create GitHub Release
+    needs: build
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/v')
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+          cache: gradle
+
+      - name: Set up Android SDK
+        uses: android-actions/setup-android@v3
+
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+
+      - name: Build debug APK
+        run: ./gradlew assembleDebug
+
+      - name: Build release APK
+        run: ./gradlew assembleRelease
+
+      - name: Create Release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: |
+            app/build/outputs/apk/debug/app-debug.apk
+            app/build/outputs/apk/release/app-release-unsigned.apk
+          generate_release_notes: true
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}