Add the native Hesychia Android client so the repo can build beyond the placeholder README.

.gitea/workflows/ci.yml

@@ -0,0 +1,34 @@
+name: CI
+
+on:
+  push:
+    branches: [master, main]
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - 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@v3
+
+      - name: Unit tests
+        run: ./gradlew :app:testProdDebugUnitTest --stacktrace
+
+      - name: Assemble debug APK
+        run: ./gradlew :app:assembleProdDebug --stacktrace
+
+      - name: Upload debug APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: hesychia-prod-debug
+          path: app/build/outputs/apk/prod/debug/*.apk
+          if-no-files-found: error