DEBUG rapid sync bug

[remenoscodes]

Test scenario that failed:

1. Create issue with 2 comments locally
2. Export to GitHub (works)
3. Run sync 3 times rapidly
4. Result: 8 comments on GitHub instead of 2

This suggests comments are being re-exported on each sync even though they should have Provider-Comment-ID tracking.

Need to investigate:

• Is Provider-Comment-ID being set during export?
• Is the comparison logic in export checking correctly?
• Are we comparing the right format of IDs?

Root cause likely in bin/git-issue-export sync logic (lines 169-242)