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/Persisence/DataControllerUPDATE.swift

@@ -0,0 +1,24 @@
+//
+//  DataControllerUPDATE.swift
+//  Feels
+//
+//  SwiftData UPDATE operations.
+//
+
+import SwiftData
+import Foundation
+
+extension DataController {
+    @discardableResult
+    func update(entryDate: Date, withMood mood: Mood) -> Bool {
+        guard let entry = getEntry(byDate: entryDate) else {
+            return false
+        }
+
+        entry.moodValue = mood.rawValue
+        saveAndRunDataListeners()
+
+        EventLogger.log(event: "update_entry")
+        return true
+    }
+}