SetClusterNodePool

Reassign a cluster slot to a different pool. If the slot is currently active, the daemon cycles Stopping/Terminated/Online so the new tags["pool"] propagates to AutoManager (containers on the worker survive — the worker preserves them across reconnects). Empty pool string = unassign (placement skips this node). Callers should ensure no jobs are currently assigned to the node; the cycle is brief but AutoManager briefly sees the node as gone.