feat: F015 shortlist management

3-panel Shortlists page with left list, center detail, right decision brief panel. AddToShortlistDialog wired into result feed cards and match detail. Full DRAFT→REVIEW_READY→FINALIZED workflow, AI-generated decision brief draft, duplicate prevention, and compare-view integration.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/stores/shortlistStore.ts

@@ -0,0 +1,20 @@
+import { create } from 'zustand'
+import type { ShortlistItemInput } from '../domain/shortlist'
+
+interface ShortlistStore {
+  selectedShortlistId: string | null
+  dialogOpen: boolean
+  pendingItem: ShortlistItemInput | null
+  setSelectedShortlist: (id: string | null) => void
+  openAddDialog: (item: ShortlistItemInput) => void
+  closeAddDialog: () => void
+}
+
+export const useShortlistStore = create<ShortlistStore>((set) => ({
+  selectedShortlistId: null,
+  dialogOpen: false,
+  pendingItem: null,
+  setSelectedShortlist: (id) => set({ selectedShortlistId: id }),
+  openAddDialog: (item) => set({ dialogOpen: true, pendingItem: item }),
+  closeAddDialog: () => set({ dialogOpen: false, pendingItem: null }),
+}))