- Call SyncAllCounters() after DeleteIssue and DeleteIssues
- Change SyncAllCounters to use excluded.last_id (allows counter to decrease)
- Delete orphaned counter rows when no issues remain for a prefix
- Add comprehensive tests in counter_sync_test.go
Fixes the issue where deleting issues left counters at high values, causing
new issues to skip IDs. Now counters accurately reflect the max existing ID.
Closes bd-49
Amp-Thread-ID: https://ampcode.com/threads/T-c3bdb8b9-d67b-4de5-901e-7ea76fc9e399
Co-authored-by: Amp <amp@ampcode.com>