Check for Changelog Updates in PRs

Automatically check if a PR that modifies code also updates the CHANGELOG:

1. Detect if the PR modifies source files (src/, lib/, etc.)

2. Check if the PR also includes changes to CHANGELOG.md or relevant changelogs

3. If significant code changes but no changelog update:

   • Extract a summary of the changes
   • Suggest what should be added to CHANGELOG
   • Request the author to add an entry

4. If CHANGELOG is updated:

   • Verify the format matches the project style
   • Check that entry is concise and user-facing
   • Ensure version number is appropriate

Provide feedback as a comment on the PR:

• ✅ CHANGELOG properly updated
• ⚠️ No CHANGELOG changes detected - please add an entry
• 🤔 CHANGELOG entry format seems off - consider [example]

This helps maintain an up-to-date CHANGELOG without manual reminders.