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/AccountEditorView.swift

@@ -21,11 +21,11 @@ struct AccountEditorView: View {
                     if isEditingDefaultAccount {
                         HStack {
                             Text(Account.defaultAccountName)
-                                .foregroundColor(.secondary)
+                                .foregroundStyle(.secondary)
                             Spacer()
                             Image(systemName: "lock.fill")
                                 .font(.caption)
-                                .foregroundColor(.secondary)
+                                .foregroundStyle(.secondary)
                         }
                     } else {
                         TextField("Account name", text: $name)
@@ -40,7 +40,7 @@ struct AccountEditorView: View {
                 } footer: {
                     if let errorMessage {
                         Text(errorMessage)
-                            .foregroundColor(.negativeRed)
+                            .foregroundStyle(Color.negativeRed)
                     } else if isEditingDefaultAccount {
                         Text("The Default account name cannot be changed.")
                     }
@@ -62,10 +62,10 @@ struct AccountEditorView: View {
             .navigationTitle(account == nil ? "New Account" : "Edit Account")
             .navigationBarTitleDisplayMode(.inline)
             .toolbar {
-                ToolbarItem(placement: .navigationBarLeading) {
+                ToolbarItem(placement: .topBarLeading) {
                     Button("Cancel") { dismiss() }
                 }
-                ToolbarItem(placement: .navigationBarTrailing) {
+                ToolbarItem(placement: .topBarTrailing) {
                     Button("Save") { saveAccount() }
                         .disabled(!isValid)
                 }