🤖 feat: add VS Code extension to release workflow

Add build-vscode-extension job to release workflow that:
- Builds the VS Code extension (make vscode-ext)
- Uploads .vsix file to GitHub Releases
- Runs in parallel with macOS/Linux builds

The extension will now be available for download from GitHub
Releases alongside the DMG and AppImage files.

_Generated with `cmux`_

Author: ammar-agent

.github/workflows/release.yml

@@ -58,3 +58,25 @@ jobs:
         run: bun x electron-builder --linux --publish always
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  build-vscode-extension:
+    name: Build and Release VS Code Extension
+    runs-on: ${{ github.repository_owner == 'coder' && 'depot-ubuntu-22.04-16' || 'ubuntu-latest' }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # Required for git describe to find tags
+
+      - uses: ./.github/actions/setup-cmux
+
+      - name: Build VS Code extension
+        run: make vscode-ext
+
+      - name: Upload VS Code extension to release
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          gh release upload ${{ github.event.release.tag_name }} \
+            vscode/cmux-*.vsix \
+            --clobber