Add POI category filters, delete item button, and fix itinerary persistence

- Expand POI categories from 5 to 7 (restaurant, bar, coffee, hotel, parking, attraction, entertainment)
- Add category filter chips with per-category API calls and caching
- Add delete button with confirmation dialog to Edit Item sheet
- Fix itinerary items not persisting: use LocalItineraryItem (SwiftData) as primary store with CloudKit sync as secondary, register model in schema

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

SportsTime/Features/Trip/Views/AddItem/POIDetailSheet.swift

@@ -171,10 +171,12 @@ struct POIDetailSheet: View {
     private var categoryColor: Color {
         switch poi.category {
         case .restaurant: return .orange
+        case .bar: return .indigo
+        case .coffee: return .brown
+        case .hotel: return .blue
+        case .parking: return .green
         case .attraction: return .yellow
         case .entertainment: return .purple
-        case .nightlife: return .indigo
-        case .museum: return .teal
         }
     }
 }