feat: merge Merkliste into Pipeline (SAVED stage) + Anfragen chat page

- Remove standalone Merkliste/Shortlists nav item; pipeline now covers the full funnel
- Add SAVED as first PipelineStage — 'Merken' on result cards lands here
- pipelineStore (Zustand) holds shared items; AddToPipelineDialog replaces AddToShortlistDialog in demand workspace
- New /demand/anfragen split-panel: searchable inquiry list + chat thread with compose
- Pipeline detail panel: KI insight, stage actions, editable notes, mock documents
- ShortlistItemCard: cards clickable → property detail, Anfrage button with inline dialog
- Supply workspace (FutureAvailability, Anfragencenter) unchanged

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

src/App.tsx

@@ -34,7 +34,7 @@ const AISearch = lazy(() => import('./pages/demand/AISearch'))
 const Results = lazy(() => import('./pages/demand/Results'))
 const MatchDetail = lazy(() => import('./pages/demand/MatchDetail'))
 const Compare = lazy(() => import('./pages/demand/Compare'))
-const Shortlists = lazy(() => import('./pages/demand/Shortlists'))
+const Anfragen = lazy(() => import('./pages/demand/Anfragen'))
 const Pipeline = lazy(() => import('./pages/demand/Pipeline'))
 const PropertyDetail = lazy(() => import('./pages/demand/PropertyDetail'))
 
@@ -74,7 +74,7 @@ function App() {
                 <Route path="/demand/results" element={<Results />} />
                 <Route path="/demand/results/:matchId" element={<MatchDetail />} />
                 <Route path="/demand/compare" element={<Compare />} />
-                <Route path="/demand/shortlists" element={<Shortlists />} />
+                <Route path="/demand/anfragen" element={<Anfragen />} />
                 <Route path="/demand/pipeline" element={<Pipeline />} />
                 <Route path="/demand/property/:propertyId" element={<PropertyDetail />} />
               </Route>