Migrate from Core Data to SwiftData

- Replace Core Data with SwiftData for iOS 18+
- Create MoodEntryModel as @Model class replacing MoodEntry entity
- Create SharedModelContainer for App Group container sharing
- Create DataController with CRUD extensions replacing PersistenceController
- Update all views and view models to use MoodEntryModel
- Update widget extension to use SwiftData
- Remove old Core Data files (Persistence*.swift, .xcdatamodeld)
- Add EntryType enum with all entry type cases
- Fix widget label truncation with proper spacing and text scaling

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Shared/FeelsApp.swift

@@ -6,6 +6,7 @@
 //
 
 import SwiftUI
+import SwiftData
 import BackgroundTasks
 import WidgetKit
 
@@ -13,8 +14,8 @@ import WidgetKit
 struct FeelsApp: App {
     @Environment(\.scenePhase) private var scenePhase
     @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
-    
-    let persistenceController = PersistenceController.shared
+
+    let dataController = DataController.shared
     @StateObject var iapManager = IAPManager()
     @AppStorage(UserDefaultsStore.Keys.firstLaunchDate.rawValue, store: GroupUserDefaults.groupDefaults) private var firstLaunchDate = Date()
     @State private var showSubscriptionFromWidget = false
@@ -25,20 +26,16 @@ struct FeelsApp: App {
             BGTask.runFillInMissingDatesTask(task: task as! BGProcessingTask)
         }
         UIApplication.shared.applicationIconBadgeNumber = 0
-//        PersistenceController.shared.clearDB()
-//        PersistenceController.shared.populateMemory()
     }
-    
+
     var body: some Scene {
         WindowGroup {
-            // build these here so when tints and other things get updated the views / their data dont
-            // have to get redrawn#imageLiteral(resourceName: "simulator_screenshot_0017B4DC-100B-42A3-A406-9019704AE275.png")
             MainTabView(dayView: DayView(viewModel: DayViewViewModel(addMonthStartWeekdayPadding: false)),
                         monthView: MonthView(viewModel: DayViewViewModel(addMonthStartWeekdayPadding: true)),
                         yearView: YearView(viewModel: YearViewModel()),
                         insightsView: InsightsView(),
                         customizeView: CustomizeView())
-            .environment(\.managedObjectContext, persistenceController.viewContext)
+            .modelContainer(dataController.container)
             .environmentObject(iapManager)
             .sheet(isPresented: $showSubscriptionFromWidget) {
                 FeelsSubscriptionStoreView()