feat(store): add In-App Purchase system with Pro subscription

Implement freemium model with StoreKit 2:
- StoreManager singleton for purchase/restore/entitlements
- ProFeature enum defining gated features
- PaywallView and OnboardingPaywallView for upsell UI
- ProGate view modifier and ProBadge component

Feature gating:
- Trip saving: 1 free trip, then requires Pro
- PDF export: Pro only with badge indicator
- Progress tab: Shows ProLockedView for free users
- Settings: Subscription management section

Also fixes pre-existing test issues with StadiumVisit
and ItineraryOption model signature changes.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

SportsTime/Features/Settings/Views/SettingsView.swift

@@ -9,9 +9,13 @@ struct SettingsView: View {
     @Environment(\.colorScheme) private var colorScheme
     @State private var viewModel = SettingsViewModel()
     @State private var showResetConfirmation = false
+    @State private var showPaywall = false
 
     var body: some View {
         List {
+            // Subscription
+            subscriptionSection
+
             // Theme Selection
             themeSection
 
@@ -187,6 +191,83 @@ struct SettingsView: View {
         .listRowBackground(Theme.cardBackground(colorScheme))
     }
 
+    // MARK: - Subscription Section
+
+    private var subscriptionSection: some View {
+        Section {
+            if StoreManager.shared.isPro {
+                // Pro user - show manage option
+                HStack {
+                    Label {
+                        VStack(alignment: .leading, spacing: 4) {
+                            Text("SportsTime Pro")
+                                .foregroundStyle(Theme.textPrimary(colorScheme))
+                            Text("Active subscription")
+                                .font(.caption)
+                                .foregroundStyle(.green)
+                        }
+                    } icon: {
+                        Image(systemName: "star.fill")
+                            .foregroundStyle(Theme.warmOrange)
+                    }
+
+                    Spacer()
+
+                    Image(systemName: "checkmark.circle.fill")
+                        .foregroundStyle(.green)
+                }
+
+                Button {
+                    if let url = URL(string: "https://apps.apple.com/account/subscriptions") {
+                        UIApplication.shared.open(url)
+                    }
+                } label: {
+                    Label("Manage Subscription", systemImage: "gear")
+                }
+            } else {
+                // Free user - show upgrade option
+                Button {
+                    showPaywall = true
+                } label: {
+                    HStack {
+                        Label {
+                            VStack(alignment: .leading, spacing: 4) {
+                                Text("Upgrade to Pro")
+                                    .foregroundStyle(Theme.textPrimary(colorScheme))
+                                Text("Unlimited trips, PDF export, progress tracking")
+                                    .font(.caption)
+                                    .foregroundStyle(Theme.textSecondary(colorScheme))
+                            }
+                        } icon: {
+                            Image(systemName: "star.fill")
+                                .foregroundStyle(Theme.warmOrange)
+                        }
+
+                        Spacer()
+
+                        Image(systemName: "chevron.right")
+                            .foregroundStyle(Theme.textMuted(colorScheme))
+                    }
+                }
+                .buttonStyle(.plain)
+
+                Button {
+                    Task {
+                        await StoreManager.shared.restorePurchases()
+                    }
+                } label: {
+                    Label("Restore Purchases", systemImage: "arrow.clockwise")
+                }
+            }
+        } header: {
+            Text("Subscription")
+        }
+        .listRowBackground(Theme.cardBackground(colorScheme))
+        .sheet(isPresented: $showPaywall) {
+            PaywallView()
+        }
+    }
+
     // MARK: - Helpers
 
     private func sportColor(for sport: Sport) -> Color {