Restored the complete 504-line sync.md documentation from global
commands directory to the repo version. This ensures:
- Single source of truth for /sync documentation
- Documentation syncs across all machines
- PC and Mac have identical command reference
Previous simplified 39-line stub has been replaced with full
documentation including phases, examples, conflict resolution,
and troubleshooting.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>