CloudKit Sync data across devices using CloudKit, iCloud key-value storage, and iCloud Drive. Covers container setup, record CRUD, queries, subscriptions, CKSyncEngine, SwiftData integration, conflict resolution, and error handling. Contents - Container and Database Setup - Workflow - CKRecord CRUD - CKQuery - CKSubscription - CKSyncEngine (iOS 17+) - SwiftData + CloudKit - NSUbiquitousKeyValueStore - iCloud Drive File Sync - Account Status and Error Handling - Conflict Resolution - Common Mistakes - Review Checklist - References Workflow 1. Choose the database scope and sync owner; verify ca…