2.0: mostrar los dos ultimos pasos del onboarding (aha moment + paywall)

completeOnboarding escribia settings.onboardingCompleted al terminar el paso
de platos. Ese flag es el que ContentView observa para cambiar de OnboardingView
a HomeView, asi que el save destruia el flujo antes de que nextStep() pudiera
pintar el paso 5. WeekReadyStepView (el aha moment de la 1.2.0) y PaywallStepView
no se han visto nunca. GA4 lo confirma: 3 onboarding_completed en 28 dias y cero
eventos con step 5 o 6.

Se separa persistir los datos de marcar el onboarding como terminado:
completeOnboarding(markFinished:) commitea platos y plan sin tocar el flag, y el
nuevo finishOnboarding() lo escribe al salir del paywall. HomeView ya difiere su
prompt premium a la segunda sesion, asi que no hay paywall duplicado.

De paso, los nombres de paso en AnalyticsService estaban desalineados: el indice
5 decia "5_paywall" cuando el paso 5 es WeekReady, y el 6 no tenia nombre.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012Ks8uUcMA9mjypVK7F2Pkt

MealMood/ViewModels/OnboardingViewModel.swift

@@ -120,8 +120,15 @@ final class OnboardingViewModel: ObservableObject {
         }
     }
 
+    /// Persists the choices made during onboarding (settings, dishes, first week).
+    ///
+    /// `markFinished` must stay `false` while the flow is still on screen: the
+    /// `onboardingCompleted` flag is what ContentView watches to swap onboarding
+    /// for the home, so writing it here would tear the flow down before the last
+    /// two steps (Week Ready and paywall) get a chance to render. Call
+    /// `finishOnboarding(context:)` once the user leaves the final step.
     @discardableResult
-    func completeOnboarding(context: ModelContext) -> Bool {
+    func completeOnboarding(context: ModelContext, markFinished: Bool = true) -> Bool {
         // Create or get settings
         let descriptor = FetchDescriptor<AppSettings>()
         let settings = (try? context.fetch(descriptor))?.first ?? {
@@ -137,7 +144,9 @@ final class OnboardingViewModel: ObservableObject {
         settings.calendarId = selectedCalendarId
         settings.lunchTime = lunchTime
         settings.dinnerTime = dinnerTime
-        settings.onboardingCompleted = true
+        if markFinished {
+            settings.onboardingCompleted = true
+        }
 
         // Create default tags if not exist
         let tagDescriptor = FetchDescriptor<Tag>()
@@ -178,6 +187,23 @@ final class OnboardingViewModel: ObservableObject {
         }
     }
 
+    /// Flips the flag ContentView watches, handing the user over to the home.
+    /// Separate from `completeOnboarding` so the data can be committed at the
+    /// dishes step while the flow stays on screen for the last two steps.
+    func finishOnboarding(context: ModelContext) {
+        let descriptor = FetchDescriptor<AppSettings>()
+        guard let settings = (try? context.fetch(descriptor))?.first else { return }
+        guard !settings.onboardingCompleted else { return }
+
+        settings.onboardingCompleted = true
+        do {
+            try context.save()
+        } catch {
+            CrashlyticsService.record(error, context: "onboarding_finish")
+            print("Onboarding finish failed: \(error)")
+        }
+    }
+
     /// Fills the first week right inside onboarding (the "aha moment" step) using
     /// the same engine as the home auto-complete. Returns the number of filled slots.
     @discardableResult