Add sync extension to community catalog (#1728)

* Add sync extension to community catalog

- Extension ID: sync
- Version: 0.1.0
- Author: bgervin
- Description: Detect and resolve drift between specs and implementation

* fix: use main branch in URLs per Copilot review

* Reorder community extensions table alphabetically

Per Copilot review feedback and EXTENSION-PUBLISHING-GUIDE.md

---------

Co-authored-by: Barry Gervin <bgervin@hotmail.com>