feat: enable automatic marketplace publishing

[jcouball]

This PR enables automatic publishing to the VS Code Marketplace and Open VSX when a release is created.

Changes

• Added publisher field to package.json (set to "main-branch")
• Uncommented the VS Code Marketplace publishing step in the publish-release.yml workflow
• Uncommented the Open VSX publishing step in the publish-release.yml workflow

Prerequisites

VS Code Marketplace

• ✅ Azure DevOps organization created (main-branch)
• ✅ Personal Access Token (PAT) generated with Marketplace (Manage) scope
• ✅ VSCE_PAT secret added to GitHub repository

Open VSX

• ⏳ Create account at https://open-vsx.org/ (sign in with GitHub)
• ⏳ Generate access token at https://open-vsx.org/user-settings/tokens
• ⏳ Add OVSX_PAT secret to GitHub repository

After Merging

When the next release-please PR is merged, the extension will automatically:

1. Create a GitHub release with a tag
2. Build and package the extension as a .vsix file
3. Upload the .vsix to the GitHub release
4. Publish to the VS Code Marketplace 🚀
5. Publish to Open VSX 🚀

The extension will be available at:

• VS Code Marketplace: https://marketplace.visualstudio.com/publishers/main-branch
• Open VSX: https://open-vsx.org/extension/main-branch/mkdocs-snippet-lens

[Copilot]

Pull request overview

This PR enables automated publishing to the VS Code Marketplace by adding the required publisher identifier and activating the marketplace publishing step in the release workflow. According to the PR description, the prerequisites (Azure DevOps organization, PAT token, and GitHub secret) are already in place.

Key Changes:

• Added publisher field to package.json with value "main-branch"
• Enabled VS Code Marketplace publishing step in the publish-release workflow
• Publishing will be triggered automatically when release-please creates a new release

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
package.json	Adds the "publisher" field identifying "main-branch" as the marketplace publisher
.github/workflows/publish-release.yml	Uncomments the VS Code Marketplace publishing step that uses the VSCE_PAT secret to authenticate with vsce publish