async getTurnCheckpointRef(turnId: string): Promise<string | undefined> {
const row = await dbGet(db, 'SELECT checkpoint_ref FROM turns WHERE id = ?1 OR event_id = ?1 LIMIT 1', [turnId]);
return row?.checkpoint_ref as string | undefined ?? undefined;
}
async getPreviousCheckpointRef(turnId: string): Promise<string | undefined> {