Migrate sync queue persistence to store adapters

docs/SETUP.md

@@ -28,6 +28,9 @@ Default local store:
 
 - `Hive` (`USE_HIVE_LOCAL_DB=true` by default)
 - first-run migration imports legacy `shared_preferences` payload when present
+- applies to both:
+  - local product state (`LocalRepository`)
+  - sync queue state (`SyncQueueRepository`)
 
 Optional migration path:
 

docs/progress.md

@@ -2,6 +2,35 @@
 
 Updated: 2026-02-15
 
+## Latest Milestone (2026-02-15): Sync Queue Storage Adapter + Hive Migration
+
+Extended the storage abstraction approach to sync queue persistence:
+
+- Added sync storage abstraction:
+  - `lib/features/sync/storage/sync_state_store.dart`
+- Added concrete sync stores:
+  - `lib/features/sync/storage/sync_state_store_shared_prefs.dart`
+  - `lib/features/sync/storage/sync_state_store_hive.dart`
+  - `lib/features/sync/storage/sync_state_store_in_memory.dart`
+  - provider wiring: `lib/features/sync/storage/sync_state_store_provider.dart`
+- Refactored sync queue repository:
+  - `lib/features/sync/sync_queue_repository.dart`
+  - no direct `shared_preferences` dependency
+  - store-agnostic read/write path via `SyncStateStore`
+  - one-time migration path from legacy shared prefs sync payload into Hive
+- Updated tests to use explicit in-memory store overrides where deterministic:
+  - `test/features/sync/sync_queue_repository_test.dart`
+  - `test/features/sync/sync_coordinator_test.dart`
+  - `test/features/local/local_repository_test.dart`
+  - `test/features/responsive/responsive_views_smoke_test.dart`
+- Added migration coverage:
+  - `test/features/sync/storage/sync_queue_hive_migration_test.dart`
+
+Validation for this milestone:
+
+- `flutter analyze` -> pass
+- `flutter test` -> pass
+
 ## Latest Milestone (2026-02-15): Local Store Adapter Layer (DB Migration Scaffold)
 
 Implemented a persistence boundary so local app state is no longer tightly coupled to `shared_preferences` internals: