Add `enabled` parameter to tool query hooks so non-plugin nodes
(LLM, Code, IfElse, etc.) avoid registering React Query observers.
Extract shared matching functions into plugin-install-check utils to
eliminate duplicate logic between the hook and the checklist.
Replace useEffect-based state sync (_pluginInstallLocked/_dimmed) with
render-time derived computation in BaseNode, breaking the cycle of
effect → node data update → re-render → effect. Extract plugin missing
check into a pure utility function for checklist reuse.
