Offline-first architecture for Kotlin Multiplatform apps — local-first reads, background sync, optimistic updates, conflict resolution, and sync state tracking. Covers: single-source-of-truth via SQLDelight, a SyncManager pattern using WorkManager/BGTaskScheduler, optimistic mutation with rollback, and a SyncState sealed class surfaced to the UI via MVI. Does NOT cover FCM-triggered sync (see push-notifications) or RPC streaming (see kotlin-rpc).
