Xcode 27: compila sin warnings y migra API deprecadas de SwiftUI

- Imports de CoreData que faltaban (MemberImportVisibility) en AccountsView,
  ImportDataView, ChartsContainerView y AddSourceView.
- Aislamiento MainActor: IsolatedDefaultValues en el target de la app,
  LinearGradient @MainActor, WatchSyncMessage nonisolated, closures de
  ReviewPromptService/MonthlyCheckInStore/AppIntents.
- Warnings de valores sin usar (SnapshotGapDetector, DashboardLayoutStore,
  OnboardingView, GoalEditorView, CoreDataStack, SettingsViewModel).
- foregroundColor→foregroundStyle, cornerRadius→clipShape,
  navigationBarLeading/Trailing→topBarLeading/Trailing,
  Task.sleep(nanoseconds:)→sleep(for:), NavigationLink(isActive:)→
  navigationDestination(isPresented:).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01F1u4K16xy7eQVtgsYNZ9Vn

PortfolioJournal/Views/Accounts/AccountsView.swift

@@ -1,4 +1,5 @@
 import SwiftUI
+import CoreData
 
 struct AccountsView: View {
     @EnvironmentObject private var iapService: IAPService
@@ -33,17 +34,17 @@ struct AccountsView: View {
                                         if account.isDefaultAccount {
                                             Image(systemName: "star.fill")
                                                 .font(.caption2)
-                                                .foregroundColor(.appWarning)
+                                                .foregroundStyle(Color.appWarning)
                                         }
                                     }
                                     Text(account.currencyCode ?? AppSettings.getOrCreate(in: CoreDataStack.shared.viewContext).currency)
                                         .font(.caption)
-                                        .foregroundColor(.secondary)
+                                        .foregroundStyle(.secondary)
                                 }
                                 Spacer()
                                 if accountStore.selectedAccount?.safeId == account.safeId && !accountStore.showAllAccounts {
                                     Image(systemName: "checkmark.circle.fill")
-                                        .foregroundColor(.appPrimary)
+                                        .foregroundStyle(Color.appPrimary)
                                 }
                             }
                         }
@@ -92,7 +93,7 @@ struct AccountsView: View {
             Text("The Default account cannot be deleted. You must keep at least one account.")
         }
         .toolbar {
-            ToolbarItem(placement: .navigationBarTrailing) {
+            ToolbarItem(placement: .topBarTrailing) {
                 Button {
                     if accountStore.canAddAccount() {
                         showingAddAccount = true