feat: add automated NPM publishing workflow with Changesets

[marcomariscal]

Summary

• Add automated NPM publishing using Changesets
• Streamline release process with GitHub Actions automation
• Add changeset validation in CI for pull requests

Key Features

🚀 Automated Releases

• One-click publishing: Merging version PR automatically publishes to NPM
• GitHub releases: Automatic release notes from changesets
• Beta support: Maintains existing beta workflow

📝 Changeset Workflow

• Developer adds changeset: bun changeset for user-facing changes
• Bot creates version PR: Automatic version bumps and changelog
• Maintainer reviews & merges: Publishing happens automatically

✅ CI Integration

• Changeset validation: PR check ensures changesets for meaningful changes
• Helpful guidance: Auto-comments when changeset needed
• Smart detection: Ignores docs, tests, internal changes

How It Works

1. Feature PR includes changeset file (this PR demonstrates!)
2. Merge PR → Changesets bot creates version PR
3. Merge version PR → Automatic NPM publish + GitHub release
4. Stay in beta by using pre-release changesets when needed

Testing This PR

This PR includes a changeset demonstrating the workflow. When merged:

1. Changesets bot will create a version PR
2. That version PR will bump from 1.0.0-beta.2 → 1.0.0-beta.3
3. Merging the version PR will publish to NPM automatically

Scripts Added

bun changeset              # Create a changeset
bun changeset:status       # Check pending changes  
bun changeset:version      # Bump versions (used by bot)
bun changeset:publish      # Publish to NPM (used by CI)

🤖 Generated with Claude Code