Add build vsix Workflow (#3600)

.github/workflows/build-vsix.yml

@@ -0,0 +1,45 @@
+name: Build VSIX
+
+on:
+  pull_request:
+    types: [labeled]
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    if: github.event.label.name == 'build'
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version-file: 'package.json'
+        cache: 'npm'
+
+    - name: Install dependencies
+      run: npm ci
+
+    - name: Install all dependencies
+      run: npm run install:all
+
+    - name: Build Extension
+      run: npm run build
+
+    - name: Upload VSIX artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: extension-vsix
+        path: bin/*.vsix
+
+    - name: Comment PR with artifact link
+      if: github.event_name == 'pull_request'
+      uses: peter-evans/create-or-update-comment@v4
+      with:
+        issue-number: ${{ github.event.pull_request.number }}
+        body: |
+          Build successful! 🚀
+          You can download the VSIX extension [here](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}).