Add GitHub Actions workflow to build and upload Linux packages

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

.github/workflows/build-linux.yml

@@ -0,0 +1,55 @@
+name: Build & Upload Linux Packages
+
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Release tag to upload assets to (e.g. v2.0.0)'
+        required: true
+        default: 'v2.0.0'
+
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Install Linux build tools
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y rpm fakeroot dpkg
+
+      - name: Build Linux packages (x64)
+        run: npm run build:linux --workspace=apps/desktop
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build Linux packages (arm64)
+        run: npm run build:linux:arm64 --workspace=apps/desktop
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: List build output
+        run: ls -lh apps/desktop/dist/
+
+      - name: Upload Linux packages to release
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ github.event.inputs.tag }}
+          files: |
+            apps/desktop/dist/*.AppImage
+            apps/desktop/dist/*.deb
+            apps/desktop/dist/*.rpm
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}