refactor: move PipelineItems from Zustand to Provider→Service→React Query

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>

src/domain/pipeline.ts

@@ -24,3 +24,17 @@ export interface PipelineItem {
   notes?: string
   assignedTo?: string
 }
+
+export interface PendingPipelineItem {
+  resultId: string
+  resultType: PipelineItem['resultType']
+  title: string
+  location?: string
+  matchScore: number
+  propertyId?: string
+  unitId?: string
+  propertyAddress?: string
+  areaLabel?: string
+  rentLabel?: string
+  availabilityLabel?: string
+}