2.0: CloudKit private-database sync replaces KV snapshot sync

Foundation for 2.1 family sharing (CKShare needs these models + container).
SwiftData cannot share across Apple IDs today, so 2.0 ships true multi-device
sync for the same account instead:

- Models made CloudKit-compatible: dropped @Attribute(.unique) on all 5,
  inline defaults on every attribute, WeekPlan.slots stored as optional
  relationship (name preserved → lightweight migration) with non-optional
  slotList facade; ~73 call sites renamed.
- Container: cloudKitDatabase .automatic, falling back to the local-only
  store when CloudKit is unavailable; failures recorded to Crashlytics.
- Entitlements: iCloud CloudKit service (container already existed);
  remote-notification background mode for push-driven sync.
- Legacy KV snapshot sync (ICloudSyncService) stays inert when CloudKit is
  active — kept only for 1.x devices.
- DeduplicationService collapses cross-device duplicates deterministically on
  launch (settings singleton, default tags with tagId remapping, same-week
  plans).
- Note: AppSettings.isPremium now syncs across same-Apple-ID devices; StoreKit
  (PremiumSyncService + Transaction.updates) remains the source of truth and
  reconciles on every launch/foreground.

All 21 unit tests pass, including ICloudSyncPremiumIsolationTests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BkanrydYtrme8wipTzWssG

MealMoodTests/AutocompleteEngineTests.swift

@@ -19,7 +19,7 @@ final class AutocompleteEngineTests: XCTestCase {
         let plan = WeekPlan(weekStartDate: Date().startOfWeek())
         let mondayDinner = MealSlot(dayOfWeek: 0, mealType: MealType.dinner.rawValue, dishId: dishA.id)
         let tuesdayDinner = MealSlot(dayOfWeek: 1, mealType: MealType.dinner.rawValue, dishId: nil)
-        plan.slots = [mondayDinner, tuesdayDinner]
+        plan.slotList = [mondayDinner, tuesdayDinner]
 
         let isValid = AutocompleteEngine.validateDrop(
             dish: dishB,
@@ -47,7 +47,7 @@ final class AutocompleteEngineTests: XCTestCase {
 
         let mondayDinner = MealSlot(dayOfWeek: 0, mealType: MealType.dinner.rawValue, dishId: fishDish.id)
         let tuesdayDinner = MealSlot(dayOfWeek: 1, mealType: MealType.dinner.rawValue, dishId: nil)
-        plan.slots = [mondayDinner, tuesdayDinner]
+        plan.slotList = [mondayDinner, tuesdayDinner]
 
         let result = AutocompleteEngine.autocomplete(
             emptySlots: [tuesdayDinner],