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/Features/Trip/Views/Wizard/TripWizardView.swift

@@ -203,7 +203,9 @@ struct TripWizardView: View {
                 // Team-First mode: fetch ALL games for the season
                 // ScenarioEPlanner will generate sliding windows across the full season
                 games = try await AppDataProvider.shared.allGames(for: preferences.sports)
+                #if DEBUG
                 print("🔍 TripWizard: Team-First mode - fetched \(games.count) games for \(preferences.sports)")
+                #endif
             } else if viewModel.planningMode == .gameFirst && !viewModel.selectedGameIds.isEmpty {
                 // Fetch all games for the selected sports within the UI date range
                 // GamePickerStep already set viewModel.startDate/endDate to a 7-day span