Reconcile async capacity state before repeating resize

Treat an asynchronous GKE node-pool resize as pending until provider operation state and actual node inventory agree. A dashboard can briefly retain the last observed node count after both managed instance groups reach zero, while the control-plane operation is still reconciling. Keep provider switching locked, poll the original resize operation, and refresh capacity evidence after it reaches a terminal state; never submit another resize merely because the UI is stale. Limits: zero nodes proves compute parking, not zero cluster or storage charges, and system workloads may intentionally remain elsewhere.

Applies when: an active-passive switch parks or wakes GKE capacity around traffic movement. Keywords: GKE scale zero node pool resize reconciliation stale capacity switch lock