feat(paywall): enhance onboarding with rich backgrounds and intro pricing

- Add themed backgrounds for each onboarding feature page:
  - Unlimited Trips: animated route map with dotted paths and traveling car
  - Export & Share: floating documents with radiating share lines
  - Track Your Journey: stadium map with pins and achievement badges
- Add sports-themed pricing page background with random glow effects
- Display introductory offer pricing in subscription rows
- Add feature bullets to each onboarding page for better value prop
- Add crown icon header and feature pills to pricing page
- Add debug button in Settings to preview onboarding flow
- Create StoreKit configuration file for testing IAP

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

SportsTime/Features/Settings/Views/SettingsView.swift

@@ -10,6 +10,7 @@ struct SettingsView: View {
     @State private var viewModel = SettingsViewModel()
     @State private var showResetConfirmation = false
     @State private var showPaywall = false
+    @State private var showOnboardingPaywall = false
 
     var body: some View {
         List {
@@ -33,6 +34,11 @@ struct SettingsView: View {
 
             // Reset
             resetSection
+
+            #if DEBUG
+            // Debug
+            debugSection
+            #endif
         }
         .scrollContentBackground(.hidden)
         .themedBackground()
@@ -44,6 +50,9 @@ struct SettingsView: View {
         } message: {
             Text("This will reset all settings to their default values.")
         }
+        .sheet(isPresented: $showOnboardingPaywall) {
+            OnboardingPaywallView(isPresented: $showOnboardingPaywall)
+        }
     }
 
     // MARK: - Theme Section
@@ -246,6 +255,31 @@ struct SettingsView: View {
         .listRowBackground(Theme.cardBackground(colorScheme))
     }
 
+    // MARK: - Debug Section
+
+    #if DEBUG
+    private var debugSection: some View {
+        Section {
+            Button {
+                showOnboardingPaywall = true
+            } label: {
+                Label("Show Onboarding Flow", systemImage: "play.circle")
+            }
+
+            Button {
+                UserDefaults.standard.removeObject(forKey: "hasSeenOnboardingPaywall")
+            } label: {
+                Label("Reset Onboarding Flag", systemImage: "arrow.counterclockwise")
+            }
+        } header: {
+            Text("Debug")
+        } footer: {
+            Text("These options are only visible in debug builds.")
+        }
+        .listRowBackground(Theme.cardBackground(colorScheme))
+    }
+    #endif
+
     // MARK: - Subscription Section
 
     private var subscriptionSection: some View {