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/DataControllerHelper.swift

@@ -0,0 +1,93 @@
+//
+//  DataControllerHelper.swift
+//  Feels
+//
+//  SwiftData helper and test data operations.
+//
+
+import SwiftData
+import Foundation
+
+extension DataController {
+    func randomEntries(count: Int) -> [MoodEntryModel] {
+        var entries = [MoodEntryModel]()
+
+        for idx in 0..<count {
+            let date = Calendar.current.date(byAdding: .day, value: -idx, to: Date())!
+            let entry = MoodEntryModel(
+                forDate: date,
+                mood: Mood.allValues.randomElement()!,
+                entryType: .listView
+            )
+            entry.timestamp = date
+            entries.append(entry)
+        }
+        return entries
+    }
+
+    func populateMemory() {
+        #if DEBUG
+        for idx in 1..<255 {
+            let date = Calendar.current.date(byAdding: .day, value: -idx, to: Date())!
+            var moodValue = Int.random(in: 2...4)
+            if idx % 5 == 0 {
+                moodValue = Int.random(in: 0...4)
+            }
+
+            let entry = MoodEntryModel(
+                forDate: date,
+                mood: Mood(rawValue: moodValue) ?? .average,
+                entryType: .listView
+            )
+            entry.timestamp = date
+            modelContext.insert(entry)
+        }
+        save()
+        #endif
+    }
+
+    /// Creates an entry that is NOT inserted into the context - used for UI placeholders
+    func generateObjectNotInArray(forDate date: Date = Date(), withMood mood: Mood = .placeholder) -> MoodEntryModel {
+        var moodValue = Int.random(in: 2...4)
+        if Int.random(in: 0...400) % 5 == 0 {
+            moodValue = Int.random(in: 0...4)
+        }
+
+        let entry = MoodEntryModel(
+            forDate: date,
+            moodValue: moodValue,
+            entryType: EntryType.listView.rawValue,
+            canEdit: false,
+            canDelete: false
+        )
+        return entry
+    }
+
+    func populateTestData() {
+        clearDB()
+
+        for idx in 1..<1000 {
+            let date = Calendar.current.date(byAdding: .day, value: -idx, to: Date())!
+            var moodValue = Int.random(in: 3...4)
+            if Int.random(in: 0...400) % 5 == 0 {
+                moodValue = Int.random(in: 0...4)
+            }
+
+            let entry = MoodEntryModel(
+                forDate: date,
+                mood: Mood(rawValue: moodValue) ?? .average,
+                entryType: .listView
+            )
+            modelContext.insert(entry)
+        }
+
+        saveAndRunDataListeners()
+    }
+
+    func longestStreak() -> [MoodEntryModel] {
+        let descriptor = FetchDescriptor<MoodEntryModel>(
+            sortBy: [SortDescriptor(\.forDate, order: .forward)]
+        )
+        return (try? modelContext.fetch(descriptor)) ?? []
+    }
+}