ci: add Gitea Actions workflows for .exe and APK builds

- build-exe.yml: Python server → PyInstaller → PaperDash.exe (windows-latest)
- build-apk.yml: Android project → Gradle → app-debug.apk (ubuntu-latest)
- Both trigger on push/PR to main when relevant paths change

.gitea/workflows/build-apk.yml

@@ -0,0 +1,58 @@
+name: Build Android APK
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "android/**"
+      - "client/**"
+      - ".gitea/workflows/build-apk.yml"
+  pull_request:
+    branches: [main]
+    paths:
+      - "android/**"
+      - "client/**"
+      - ".gitea/workflows/build-apk.yml"
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: "17"
+          distribution: "temurin"
+
+      - name: Sync client assets
+        run: |
+          cp client/index.html android/app/src/main/assets/index.html
+          cp client/style.css android/app/src/main/assets/style.css
+          cp client/app.js android/app/src/main/assets/app.js
+
+      - name: Setup Android SDK
+        uses: android-actions/setup-android@v3
+        with:
+          cmdline-tools-version: 11076708
+          platforms: "platform-34"
+          build-tools: "34.0.0"
+
+      - name: Build APK (debug)
+        working-directory: android
+        run: |
+          chmod +x gradlew || true
+          ./gradlew assembleDebug
+        env:
+          GRADLE_OPTS: "-Dorg.gradle.daemon=false"
+
+      - name: Upload debug APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: PaperDash-debug.apk
+          path: android/app/build/outputs/apk/debug/app-debug.apk
+          if-no-files-found: error

.gitea/workflows/build-exe.yml

@@ -0,0 +1,52 @@
+name: Build Server .exe
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "server/**"
+      - ".gitea/workflows/build-exe.yml"
+  pull_request:
+    branches: [main]
+    paths:
+      - "server/**"
+      - ".gitea/workflows/build-exe.yml"
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: windows-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: "pip"
+
+      - name: Install dependencies
+        run: |
+          cd server
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+
+      - name: Run tests
+        run: |
+          cd server
+          pip install pytest pytest-asyncio
+          pytest tests/ -v
+
+      - name: Build .exe
+        run: |
+          cd server
+          python build_exe.py
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: PaperDash.exe
+          path: server/dist/PaperDash.exe
+          if-no-files-found: error