ci: add Android APK build job

New build_android job running on ubuntu-latest:
- setup-java@v4 with JDK 17 (Temurin) matching compileOptions
- npm ci + build:userscript (same as iOS job)
- Gradle cache keyed on wrapper + root/app build.gradle hashes
- ./gradlew assembleRelease --no-daemon
- Artifact: Movix-Android-<version>, retention 30 days

Both jobs now triggered independently via workflow_dispatch booleans
(build_ios / build_android, both default true).
APK is debug-signed (falls back to signingConfigs.debug when no
keystore.properties) — suitable for sideloading.

https://claude.ai/code/session_01X52sah6aUu3ou26uJWHgzr

.github/workflows/build.yml

@@ -1,4 +1,4 @@
-name: Build iOS IPA (Unsigned)
+name: Build Applications
 
 on:
   workflow_dispatch:
@@ -7,6 +7,10 @@ on:
         description: 'Build iOS IPA (unsigned)'
         type: boolean
         default: true
+      build_android:
+        description: 'Build Android APK'
+        type: boolean
+        default: true
 
 jobs:
   build_ios:
@@ -112,3 +116,70 @@ jobs:
           path: app/ios/build/MovixApp-${{ steps.version.outputs.version }}.ipa
           retention-days: 30
           if-no-files-found: error
+
+  build_android:
+    name: Build Android APK
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    if: ${{ inputs.build_android }}
+
+    defaults:
+      run:
+        working-directory: app
+
+    steps:
+      - name: ⬇️ • Checkout
+        uses: actions/checkout@v4
+
+      - name: 📀 • Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: ☕ • Setup JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+
+      - name: 💾 • Cache Node Modules
+        uses: actions/cache@v4
+        with:
+          path: app/node_modules
+          key: node-modules-android-${{ hashFiles('app/package-lock.json') }}
+          restore-keys: |
+            node-modules-android-
+
+      - name: 🗂️ • Install Node Dependencies
+        run: npm ci --legacy-peer-deps
+
+      - name: 📝 • Generate userscript source
+        run: npm run build:userscript
+
+      - name: 💾 • Cache Gradle
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: gradle-${{ hashFiles('app/android/gradle/wrapper/gradle-wrapper.properties', 'app/android/build.gradle', 'app/android/app/build.gradle') }}
+          restore-keys: |
+            gradle-
+
+      - name: 📖 • Read app version
+        id: version
+        run: echo "version=$(jq -r '.version' version.json)" >> "$GITHUB_OUTPUT"
+
+      - name: 🤖 • Build Android APK
+        run: |
+          cd android
+          chmod +x gradlew
+          ./gradlew assembleRelease --no-daemon
+
+      - name: 🌍 • Upload APK artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: Movix-Android-${{ steps.version.outputs.version }}
+          path: app/android/app/build/outputs/apk/release/app-release.apk
+          retention-days: 30
+          if-no-files-found: error