Add Forgejo Actions CI and APK build workflows

ci.yml: flutter analyze + flutter test on every push, runs in
  ghcr.io/cirruslabs/flutter:stable container (includes Flutter, Dart,
  Java, Android SDK)
build.yml: release APK build on main push, uploaded as workflow artifact
  (downloadable from Forgejo Actions UI, retained 30 days)

No secrets required. Uses existing swarm-runner.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.forgejo/workflows/build.yml

@@ -0,0 +1,27 @@
+name: Build APK
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  build:
+    name: Build release APK
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/cirruslabs/flutter:stable
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: flutter pub get
+
+      - name: Build release APK
+        run: flutter build apk --release
+
+      - name: Upload APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: fabledapp-${{ github.sha }}
+          path: build/app/outputs/flutter-apk/app-release.apk
+          retention-days: 30

.forgejo/workflows/ci.yml

@@ -0,0 +1,23 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  analyze:
+    name: Analyze & test
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/cirruslabs/flutter:stable
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: flutter pub get
+
+      - name: Analyze
+        run: flutter analyze
+
+      - name: Test
+        run: flutter test