ci: add GitHub Actions workflow for automated build

- Build on push/PR to main and manual dispatch
- Archive with Release configuration, no code signing
- Upload NetworkStatusBar.app as artifact

Author: cnfatal

.github/workflows/build.yml

@@ -0,0 +1,38 @@
+name: Build
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Select Xcode
+        run: sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
+
+      - name: Build
+        run: |
+          xcodebuild archive \
+            -scheme NetworkStatusBar \
+            -configuration Release \
+            -archivePath ${{ runner.temp }}/NetworkStatusBar.xcarchive \
+            CODE_SIGN_IDENTITY="-" \
+            CODE_SIGNING_REQUIRED=NO \
+            CODE_SIGNING_ALLOWED=NO
+
+      - name: Export app
+        run: |
+          cp -R "${{ runner.temp }}/NetworkStatusBar.xcarchive/Products/Applications/NetworkStatusBar.app" \
+            "${{ runner.temp }}/NetworkStatusBar.app"
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: NetworkStatusBar
+          path: ${{ runner.temp }}/NetworkStatusBar.app