feat: F010 unified result feed

Replace monolithic Results.tsx with decomposed component architecture:
- 8 new components in src/components/results/ (ResultTypeBadge, ResultConfidenceSummary, FeedEmptyState, FeedSkeleton, ResultFeedHeader, ResultFilterBar, UnifiedResultCard, UnifiedResultFeed)
- Reuses existing useUnifiedResults hook and compareStore
- FUTURE_AVAILABILITY cards always display non-dismissable disclaimer
- Filter by result type + sort by score/area/rent

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

src/components/results/FeedEmptyState.tsx

@@ -0,0 +1,14 @@
+import { EmptyState } from '../ui'
+
+export function FeedEmptyState({ filtered }: { filtered?: boolean }) {
+  return (
+    <EmptyState
+      title={filtered ? 'Kein Treffer für diesen Filter' : 'Keine Treffer gefunden'}
+      description={
+        filtered
+          ? 'Wechseln Sie den Filter oder passen Sie die Suchkriterien an.'
+          : 'Starten Sie eine neue Suche oder erweitern Sie die Suchkriterien.'
+      }
+    />
+  )
+}