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/Utilities/DashboardLayoutStore.swift

@@ -74,7 +74,7 @@ enum DashboardLayoutStore {
 
         var merged: [DashboardSectionConfig] = []
         for config in decoded {
-            if let section = DashboardSection(rawValue: config.id) {
+            if DashboardSection(rawValue: config.id) != nil {
                 merged.append(config)
             } else {
                 continue

PortfolioJournal/Utilities/Extensions/Color+Extensions.swift

@@ -167,6 +167,7 @@ extension Color {
 
 // MARK: - Gradient Extensions
 
+@MainActor
 extension LinearGradient {
     static let appPrimaryGradient = LinearGradient(
         colors: [Color.appPrimary, Color.appPrimary.lighter()],

PortfolioJournal/Utilities/MonthlyCheckInStore.swift

@@ -66,7 +66,7 @@ enum MonthlyCheckInStore {
     }
 
     static func entry(for date: Date) -> MonthlyCheckInEntry? {
-        fetchEntry(for: monthKey(for: date)).map(makeCheckInEntry)
+        fetchEntry(for: monthKey(for: date)).map { makeCheckInEntry($0) }
     }
 
     static func allEntries() -> [(date: Date, entry: MonthlyCheckInEntry)] {

PortfolioJournal/Utilities/SnapshotGapDetector.swift

@@ -31,7 +31,6 @@ enum SnapshotGapDetector {
     /// Only months strictly between two known snapshots count — a source's
     /// trailing "not updated in a while" is handled elsewhere (pending updates).
     static func detectGaps(sources: [InvestmentSource], snapshots: [Snapshot]) -> [Gap] {
-        let calendar = Calendar.current
         let snapshotsBySource = Dictionary(grouping: snapshots) { $0.source?.id }
         var gaps: [Gap] = []