Fix crash al abrir Import Data en Mac Catalyst (@EnvironmentObject no heredado en sheets)

ImportDataView usa @EnvironmentObject (iapService/accountStore/tabSelection).
En Mac (Designed for iPad) las sheets no heredan el environment vía
PresentationHostingController → EnvironmentObject.error() / SIGTRAP al abrir
Import Data (ImportDataView.swift:247, shouldShowAccountSelection). Reinyectados
los 3 objects en las sheets de Settings, Dashboard y Onboarding.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01L2p3gUZRNWW388rWFRjiU7

PortfolioJournal/Views/Onboarding/OnboardingView.swift

@@ -13,6 +13,12 @@ struct OnboardingView: View {
     @State private var showingImportSheet = false
     @State private var showingAddSource = false
 
+    // Forwarded into the ImportDataView sheet — sheets don't inherit
+    // @EnvironmentObject on Mac Catalyst, which crashed the import screen.
+    @EnvironmentObject private var iapService: IAPService
+    @EnvironmentObject private var accountStore: AccountStore
+    @EnvironmentObject private var tabSelection: TabSelectionStore
+
     private let pages: [OnboardingPage] = [
         OnboardingPage(
             icon: "chart.line.uptrend.xyaxis",
@@ -123,6 +129,9 @@ struct OnboardingView: View {
         }
         .sheet(isPresented: $showingImportSheet) {
             ImportDataView(importContext: .onboarding)
+                .environmentObject(iapService)
+                .environmentObject(accountStore)
+                .environmentObject(tabSelection)
         }
         .sheet(isPresented: $showingAddSource) {
             AddSourceView()