PipelineItems are domain data and must not live in Zustand. Moves the
full stack to the correct layer: MockupPipelineProvider (localStorage
persistence + seed fallback) → pipelineService → usePipeline hooks
(useQuery for reads, useMutation for writes with cache invalidation).
pipelineStore is now UI-only: dialogOpen, pendingItem, openSavedDialog,
closeSavedDialog. All consumers updated to use the new hooks.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Benjamin Sutter