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/Models/CloudKit/CKModels.swift

@@ -636,27 +636,37 @@ nonisolated struct CKTripPoll {
         guard let pollIdString = record[CKTripPoll.pollIdKey] as? String,
               let pollId = UUID(uuidString: pollIdString)
         else {
+            #if DEBUG
             print("CKTripPoll.toPoll: Failed to parse pollId")
+            #endif
             return nil
         }
 
         guard let title = record[CKTripPoll.titleKey] as? String else {
+            #if DEBUG
             print("CKTripPoll.toPoll: Missing title for poll \(pollId)")
+            #endif
             return nil
         }
 
         guard let ownerId = record[CKTripPoll.ownerIdKey] as? String else {
+            #if DEBUG
             print("CKTripPoll.toPoll: Missing ownerId for poll \(pollId)")
+            #endif
             return nil
         }
 
         guard let shareCode = record[CKTripPoll.shareCodeKey] as? String else {
+            #if DEBUG
             print("CKTripPoll.toPoll: Missing shareCode for poll \(pollId)")
+            #endif
             return nil
         }
 
         guard let createdAt = record[CKTripPoll.createdAtKey] as? Date else {
+            #if DEBUG
             print("CKTripPoll.toPoll: Missing createdAt for poll \(pollId)")
+            #endif
             return nil
         }
 
@@ -669,11 +679,15 @@ nonisolated struct CKTripPoll {
             do {
                 tripSnapshots = try JSONDecoder().decode([Trip].self, from: tripsData)
             } catch {
+                #if DEBUG
                 print("CKTripPoll.toPoll: Failed to decode tripSnapshots for poll \(pollId): \(error)")
+                #endif
                 // Return poll with empty trips rather than failing completely
             }
         } else {
+            #if DEBUG
             print("CKTripPoll.toPoll: Missing tripSnapshots data for poll \(pollId)")
+            #endif
         }
 
         var poll = TripPoll(