fix: 13 audit fixes — memory, concurrency, performance, accessibility

Critical:
- ProgressViewModel: use single stored ModelContext instead of creating
  new ones per operation (deleteVisit silently no-op'd)
- ProgressViewModel: convert expensive computed properties to stored
  with explicit recompute after mutations (3x recomputation per render)

Memory:
- AnimatedSportsIcon: replace recursive GCD asyncAfter with Task loop,
  cancelled in onDisappear (19 unkillable timer chains)
- ItineraryItemService: remove [weak self] from actor Task (semantically
  wrong, silently drops flushPendingUpdates)
- VisitPhotoService: remove [weak self] from @MainActor Task closures

Concurrency:
- StoreManager: replace nested MainActor.run{Task{}} with direct await
  in listenForTransactions (fire-and-forget race)
- VisitPhotoService: move JPEG encoding/file writing off MainActor via
  nonisolated static helper + Task.detached
- SportsIconImageGenerator: replace GCD dispatch with Task.detached for
  structured concurrency compliance

Performance:
- Game/RichGame: cache DateFormatters as static lets instead of
  allocating per-call (hundreds of allocations in schedule view)
- TripDetailView: wrap ~10 routeWaypoints print() in #if DEBUG, remove
  2 let _ = print() from TripMapView.body (fires every render)

Accessibility:
- GameRow: add combined VoiceOver label (was reading abbreviations
  letter-by-letter)
- Sport badges: add accessibilityLabel to prevent SF symbol name readout
- SportsTimeApp: post UIAccessibility.screenChanged after bootstrap
  completes so VoiceOver users know app is ready

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

SportsTime/Core/Models/Domain/Game.swift

@@ -17,6 +17,36 @@
 
 import Foundation
 
+// MARK: - Cached Formatters
+
+private enum GameFormatters {
+    static let timeFormatter: DateFormatter = {
+        let f = DateFormatter()
+        f.timeStyle = .short
+        return f
+    }()
+    static let dateFormatter: DateFormatter = {
+        let f = DateFormatter()
+        f.dateStyle = .medium
+        return f
+    }()
+    static let dayOfWeekFormatter: DateFormatter = {
+        let f = DateFormatter()
+        f.dateFormat = "EEEE"
+        return f
+    }()
+    static let localTimeFormatter: DateFormatter = {
+        let f = DateFormatter()
+        f.dateFormat = "h:mm a z"
+        return f
+    }()
+    static let localTimeShortFormatter: DateFormatter = {
+        let f = DateFormatter()
+        f.dateFormat = "h:mm a"
+        return f
+    }()
+}
+
 struct Game: Identifiable, Codable, Hashable {
     let id: String  // Canonical ID: "game_mlb_2026_bos_nyy_0401"
     let homeTeamId: String  // FK: "team_mlb_bos"
@@ -58,21 +88,15 @@ struct Game: Identifiable, Codable, Hashable {
     var startTime: Date { dateTime }
 
     var gameTime: String {
-        let formatter = DateFormatter()
-        formatter.timeStyle = .short
-        return formatter.string(from: dateTime)
+        GameFormatters.timeFormatter.string(from: dateTime)
     }
 
     var formattedDate: String {
-        let formatter = DateFormatter()
-        formatter.dateStyle = .medium
-        return formatter.string(from: dateTime)
+        GameFormatters.dateFormatter.string(from: dateTime)
     }
 
     var dayOfWeek: String {
-        let formatter = DateFormatter()
-        formatter.dateFormat = "EEEE"
-        return formatter.string(from: dateTime)
+        GameFormatters.dayOfWeekFormatter.string(from: dateTime)
     }
 }
 
@@ -106,16 +130,14 @@ struct RichGame: Identifiable, Hashable, Codable {
 
     /// Game time formatted in the stadium's local timezone with timezone indicator
     var localGameTime: String {
-        let formatter = DateFormatter()
-        formatter.dateFormat = "h:mm a z"
+        let formatter = GameFormatters.localTimeFormatter
         formatter.timeZone = stadium.timeZone ?? .current
         return formatter.string(from: game.dateTime)
     }
 
     /// Game time formatted in the stadium's local timezone without timezone indicator
     var localGameTimeShort: String {
-        let formatter = DateFormatter()
-        formatter.dateFormat = "h:mm a"
+        let formatter = GameFormatters.localTimeShortFormatter
         formatter.timeZone = stadium.timeZone ?? .current
         return formatter.string(from: game.dateTime)
     }