(Admin) Sync GitHub

Manually triggers a GitHub sync. **Administrators only** — the caller's session email must match the configured `ADMIN_EMAIL`; an API key cannot reach this route. Incremental by default: only issues updated since the last sync are refetched. The run is guarded by a 10-minute Redis lock, so a concurrent attempt fails with `409` rather than double-syncing. The response is the updated sync record.

curl -X POST "https://example.com/api/v1/github/admin/sync"

{  "success": true,  "message": "Manual GitHub sync completed successfully",  "data": {    "id": "sync_123",    "projectName": "owner/repo",    "projectUrl": "https://github.com/owner/repo",    "issueCount": 120,    "onlyIssueCount": 70,    "prCount": 50,    "todoCount": 40,    "inProgressCount": 30,    "doneCount": 50,    "syncedAt": "2026-04-26T10:00:00.000Z",    "nextSyncAt": "2026-04-26T22:00:00.000Z"  }}