Syncing from main

Method	Path	Description
POST	/api/projects/{id}/chat-sessions/{sessionId}/jobs/sync-branch	Start a sync with an empty body, or continue a paused one with { userResponse }.
GET	/api/projects/{id}/chat-sessions/{sessionId}/jobs/sync-branch/{syncBranchJobId}	Poll. Statuses are pending, running, awaiting_decision, completed, failed, cancelled.
POST	/api/projects/{id}/chat-sessions/{sessionId}/jobs/sync-branch/{syncBranchJobId}/cancel	Cancel and reset.