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/Home/Views/HomeView.swift

@@ -479,10 +479,7 @@ struct SavedTripsListView: View {
     @State private var showDebugPoll = false
     #endif
 
-    /// Trips sorted by most cities (stops) first
-    private var sortedTrips: [SavedTrip] {
-        trips.sorted { ($0.trip?.stops.count ?? 0) > ($1.trip?.stops.count ?? 0) }
-    }
+    @State private var sortedTrips: [SavedTrip] = []
 
     /// Trips as domain objects for poll creation
     private var tripsForPollCreation: [Trip] {
@@ -501,6 +498,9 @@ struct SavedTripsListView: View {
             .padding(Theme.Spacing.md)
         }
         .themedBackground()
+        .onChange(of: trips, initial: true) { _, newTrips in
+            sortedTrips = newTrips.sorted { ($0.trip?.stops.count ?? 0) > ($1.trip?.stops.count ?? 0) }
+        }
         .task {
             guard !hasLoadedPolls else { return }
             hasLoadedPolls = true