fix: 14 audit fixes — concurrency, memory, performance, accessibility

Second audit round addressing data races, task stacking, unbounded
caches, and VoiceOver gaps across 7 files.

Concurrency:
- Move NSItemProvider @State access into MainActor block (3 drop handlers)
- Cancel stale ScheduleViewModel tasks on rapid filter changes

Memory:
- Replace unbounded image dict with LRUCache(countLimit: 50)
- Replace demo-mode asyncAfter with cancellable Task

Performance:
- Wrap debug NBA print() in #if DEBUG
- Cache visitsById via @State + onChange instead of per-render computed
- Pre-compute sportProgressFractions in ProgressViewModel
- Replace allGames computed property with hasGames bool check
- Cache sortedTrips via @State + onChange in SavedTripsListView

Accessibility:
- Add combined VoiceOver label to progress ring
- Combine away/home team text into single readable phrase
- Hide decorative StadiumDetailSheet icon from VoiceOver
- Add explicit accessibilityLabel to SportFilterChip
- Add combined accessibilityLabel to GameRowView

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

SportsTime/Features/Trip/Views/TripDetailView.swift

@@ -35,6 +35,7 @@ struct TripDetailView: View {
     @State private var loadedGames: [String: RichGame] = [:]
     @State private var isLoadingGames = false
     @State private var hasAppliedDemoSelection = false
+    @State private var demoSaveTask: Task<Void, Never>?
 
     // Itinerary items state
     @State private var itineraryItems: [ItineraryItem] = []
@@ -122,10 +123,10 @@ struct TripDetailView: View {
                 // Demo mode: auto-favorite the trip
                 if isDemoMode && !hasAppliedDemoSelection && !isSaved {
                     hasAppliedDemoSelection = true
-                    DispatchQueue.main.asyncAfter(deadline: .now() + DemoConfig.selectionDelay + 0.5) {
-                        if !isSaved {
-                            saveTrip()
-                        }
+                    demoSaveTask = Task {
+                        try? await Task.sleep(for: .seconds(DemoConfig.selectionDelay + 0.5))
+                        guard !Task.isCancelled, !isSaved else { return }
+                        saveTrip()
                     }
                 }
             }
@@ -137,7 +138,10 @@ struct TripDetailView: View {
                 }
                 recomputeSections()
             }
-            .onDisappear { subscriptionCancellable?.cancel() }
+            .onDisappear {
+                subscriptionCancellable?.cancel()
+                demoSaveTask?.cancel()
+            }
             .onChange(of: itineraryItems) { _, newItems in
                 handleItineraryItemsChange(newItems)
                 recomputeSections()
@@ -715,10 +719,10 @@ struct TripDetailView: View {
 
         provider.loadObject(ofClass: NSString.self) { item, _ in
             guard let droppedId = item as? String,
-                  let itemId = UUID(uuidString: droppedId),
-                  let droppedItem = self.itineraryItems.first(where: { $0.id == itemId }) else { return }
+                  let itemId = UUID(uuidString: droppedId) else { return }
 
             Task { @MainActor in
+                guard let droppedItem = self.itineraryItems.first(where: { $0.id == itemId }) else { return }
                 let day = self.findDayForTravelSegment(segment)
                 // Place at beginning of day (sortOrder before existing items)
                 let minSortOrder = self.itineraryItems
@@ -743,11 +747,11 @@ struct TripDetailView: View {
 
         provider.loadObject(ofClass: NSString.self) { item, _ in
             guard let droppedId = item as? String,
-                  let itemId = UUID(uuidString: droppedId),
-                  let droppedItem = self.itineraryItems.first(where: { $0.id == itemId }),
-                  droppedItem.id != targetItem.id else { return }
+                  let itemId = UUID(uuidString: droppedId) else { return }
 
             Task { @MainActor in
+                guard let droppedItem = self.itineraryItems.first(where: { $0.id == itemId }),
+                      droppedItem.id != targetItem.id else { return }
                 // Place before target item using midpoint insertion
                 let itemsInDay = self.itineraryItems.filter { $0.day == targetItem.day && $0.id != droppedItem.id }
                     .sorted { $0.sortOrder < $1.sortOrder }
@@ -772,10 +776,10 @@ struct TripDetailView: View {
 
         provider.loadObject(ofClass: NSString.self) { item, _ in
             guard let droppedId = item as? String,
-                  let itemId = UUID(uuidString: droppedId),
-                  let droppedItem = self.itineraryItems.first(where: { $0.id == itemId }) else { return }
+                  let itemId = UUID(uuidString: droppedId) else { return }
 
             Task { @MainActor in
+                guard let droppedItem = self.itineraryItems.first(where: { $0.id == itemId }) else { return }
                 // Calculate sortOrder: append at end of day's items
                 let maxSortOrder = self.itineraryItems
                     .filter { $0.day == day && $0.id != droppedItem.id }