Use this skill for any implementation, review, debugging, migration, or modernization change that touches SwiftData surfaces, including @Model, @Relationship, relationship append, inverse relationships, graph-root insertion, @Attribute, @Transient, #Predicate, @Query, FetchDescriptor, ModelContainer, ModelContext, context.insert, save/autosave, ModelConfiguration, ModelActor, SchemaMigrationPlan, VersionedSchema, persistent history, CloudKit sync, #Index, #Unique, inheritance, or Core Data coexistence.
