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/Views/MonthView/MonthView.swift

@@ -162,7 +162,7 @@ struct MonthView: View {
 struct MonthCard: View {
     let month: Int
     let year: Int
-    let entries: [MoodEntry]
+    let entries: [MoodEntryModel]
     let moodTint: MoodTints
     let imagePack: MoodImages
     let textColor: Color
@@ -177,7 +177,7 @@ struct MonthCard: View {
 
     private var metrics: [MoodMetrics] {
         let (startDate, endDate) = Date.dateRange(monthInt: month, yearInt: year)
-        let monthEntries = PersistenceController.shared.getData(startDate: startDate, endDate: endDate, includedDays: [1,2,3,4,5,6,7])
+        let monthEntries = DataController.shared.getData(startDate: startDate, endDate: endDate, includedDays: [1,2,3,4,5,6,7])
         return Random.createTotalPerc(fromEntries: monthEntries)
     }
 
@@ -250,7 +250,7 @@ struct MonthCard: View {
 
 // MARK: - Heatmap Cell
 struct HeatmapCell: View {
-    let entry: MoodEntry
+    let entry: MoodEntryModel
     let moodTint: MoodTints
     let isFiltered: Bool