fix: codebase audit fixes — safety, accessibility, and production hygiene

Address 16 issues from external audit:
- Move StoreKit transaction listener ownership to StoreManager singleton with proper deinit
- Remove noisy VoiceOver announcements, add missing accessibility on StatPill and BootstrapLoadingView
- Replace String @retroactive Identifiable with IdentifiableShareCode wrapper
- Add crash guard in AchievementEngine getContributingVisitIds + cache stadium lookups
- Pre-compute GamesHistoryViewModel filtered properties to avoid redundant SwiftUI recomputation
- Remove force-unwraps in ProgressMapView with safe guard-let fallback
- Add diff-based update gating in ItineraryTableViewWrapper to prevent unnecessary reloads
- Replace deprecated UIScreen.main with UIWindowScene lookup
- Add deinit task cancellation in ScheduleViewModel and SuggestedTripsGenerator
- Wrap ~234 unguarded print() calls across 27 files in #if DEBUG

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

SportsTime/Core/Store/StoreManager.swift

@@ -73,22 +73,33 @@ final class StoreManager {
         products.first { $0.id == "com.88oakapps.SportsTime.pro.annual2" }
     }
 
+    // MARK: - Transaction Listener
+
+    nonisolated(unsafe) private var transactionListenerTask: Task<Void, Never>?
+
     // MARK: - Initialization
 
     private init() {}
 
+    deinit {
+        transactionListenerTask?.cancel()
+    }
+
     // MARK: - Product Loading
 
     func loadProducts() async {
         isLoading = true
         error = nil
 
+        #if DEBUG
         print("[StoreManager] Loading products for IDs: \(Self.proProductIDs)")
+        #endif
 
         do {
             let fetchedProducts = try await Product.products(for: Self.proProductIDs)
             products = fetchedProducts
 
+            #if DEBUG
             print("[StoreManager] Loaded \(fetchedProducts.count) products:")
             for product in fetchedProducts {
                 print("[StoreManager]   - \(product.id): \(product.displayPrice) (\(product.displayName))")
@@ -101,16 +112,21 @@ final class StoreManager {
                     }
                 }
             }
+            #endif
 
             // Treat an empty fetch as a configuration issue so UI can show a useful fallback.
             if fetchedProducts.isEmpty {
+                #if DEBUG
                 print("[StoreManager] WARNING: No products returned — check Configuration.storekit")
+                #endif
                 error = .productNotFound
             }
         } catch {
             products = []
             self.error = .productNotFound
+            #if DEBUG
             print("[StoreManager] ERROR loading products: \(error)")
+            #endif
         }
 
         isLoading = false
@@ -289,10 +305,11 @@ final class StoreManager {
         return "unknown"
     }
 
-    // MARK: - Transaction Listener
+    // MARK: - Transaction Listening
 
-    func listenForTransactions() -> Task<Void, Never> {
-        Task.detached {
+    func startListeningForTransactions() {
+        transactionListenerTask?.cancel()
+        transactionListenerTask = Task.detached {
             for await result in Transaction.updates {
                 if case .verified(let transaction) = result {
                     await transaction.finish()