Add npm publish to CD workflow

[liplus-lin-lay]

Summary

Add npm publish step to the existing CD workflow (.github/workflows/cd.yml) so that tagging a release automatically publishes the npm package alongside the .mcpb asset and GitHub Release.

Current state

• CD builds .mcpb and creates a GitHub Release on tag push
• • npm publish is done manually (cd mcp-server && npm publish)

Goal

Tag push (v*) triggers:

1. .mcpb build + GitHub Release (existing)
2. 2. npm publish of mcp-server/ package (new)

Requirements

• Add NPM_TOKEN to GitHub repository secrets
• • Add npm publish step to CD workflow after release creation
• • • Version in mcp-server/package.json should match the git tag
• • • • Only publish on non-prerelease tags (or configure prerelease dist-tag)