Forgejo's create-issue API expects `labels` as `[int64]` (label IDs),
not `[{"name": "..."}]` like GitHub. The previous format caused a JSON
unmarshal error, silently returning null instead of creating the issue.
Changes:
- Split label step to create-if-missing then look up the ID
- Pass label ID as integer to issue creation: `labels: [169]`
- Add error handling: log API response if issue creation returns null
- Also cleaned up another duplicate upstream-sync label
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
