Add GitHub Actions workflow for publishing VS Code extension

.github/workflows/publish.yml

@@ -0,0 +1,40 @@
+name: Publish VS Code Extension
+
+on:
+  push:
+    branches:
+      - main
+
+concurrency:
+  group: marketplace-publish-main
+  cancel-in-progress: true
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies
+        run: npm install --frozen-lockfile
+
+      - name: Build
+        run: npm run compile
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Publish to VS Code Marketplace
+        env:
+          VSCE_PAT: ${{ secrets.VSCE_PAT }}
+        run: npx @vscode/vsce publish -p "$VSCE_PAT"