feat: add manual trigger support to release workflow

[prosdev]

Summary

Adds workflow_dispatch to the release workflow to allow manual triggering from the GitHub Actions UI.

Changes

• ✅ Added workflow_dispatch trigger to release workflow
• ✅ Allows manual triggering from Actions tab → Release → Run workflow

Use Cases

• Re-run failed releases
• Test release workflow
• Manually trigger releases when needed

How to Use

1. Go to Actions → Release workflow
2. Click "Run workflow" button
3. Select branch (usually main)
4. Click "Run workflow"

The workflow will run the same steps as automatic releases:

• Check for changesets (creates version PR if found)
• Check for unpublished packages (publishes if found)
• Create GitHub releases for successfully published packages