Add GitHub Actions workflow to build Android APK

.github/workflows/build-apk.yml

@@ -0,0 +1,51 @@
+name: Build Android APK
+
+on:
+  push:
+    branches: [ main, master ]
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 18
+
+      - name: Setup Java JDK
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '17'
+
+      - name: Install Frontend Dependencies & Build
+        run: |
+          cd frontend
+          npm install
+          npm run build
+
+      - name: Setup Capacitor and Build Android
+        run: |
+          cd frontend
+          npx cap init AIVideoApp com.aivideo.app --web-dir build || true
+          npx cap add android || true
+          npx cap sync android
+
+      - name: Build Debug APK with Gradle
+        run: |
+          cd frontend/android
+          chmod +x gradlew
+          ./gradlew assembleDebug
+
+      - name: Upload APK Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: app-debug-apk
+          path: frontend/android/app/build/outputs/apk/debug/app-debug.apk
+