adding packages

packages/pocketbase_sync/lib/repo/sync_repository.dart

@@ -0,0 +1,61 @@
+import 'dart:async';
+
+/// Wraps your data with sync metadata (Dirty flags, tombstones, versions)
+class SyncRecord<T> {
+  final String id;
+  final T data;
+
+  /// Server's timestamp. Null if created locally and never synced.
+  final DateTime? serverUpdatedAt;
+
+  /// Snapshot of data before local edits (Critical for 3-way merge).
+  final T? baseData;
+
+  /// True if local data differs from server data.
+  final bool isDirty;
+
+  /// True if marked for deletion (Soft Delete).
+  final bool isDeleted;
+
+  /// When the soft delete happened (For Retention Policy).
+  final DateTime? deletedAt;
+
+  SyncRecord({
+    required this.id,
+    required this.data,
+    this.serverUpdatedAt,
+    this.baseData,
+    this.isDirty = false,
+    this.isDeleted = false,
+    this.deletedAt,
+  });
+
+  SyncRecord<T> copyWith({
+    T? data,
+    DateTime? serverUpdatedAt,
+    T? baseData,
+    bool? isDirty,
+    bool? isDeleted,
+    DateTime? deletedAt,
+  }) {
+    return SyncRecord<T>(
+      id: id,
+      data: data ?? this.data,
+      serverUpdatedAt: serverUpdatedAt ?? this.serverUpdatedAt,
+      baseData: baseData ?? this.baseData,
+      isDirty: isDirty ?? this.isDirty,
+      isDeleted: isDeleted ?? this.isDeleted,
+      deletedAt: deletedAt ?? this.deletedAt,
+    );
+  }
+}
+
+/// Abstract Storage Interface
+abstract class SyncRepository<T> {
+  Future<List<SyncRecord<T>>> getAll();
+  Future<SyncRecord<T>?> get(String id);
+  Future<void> save(SyncRecord<T> record);
+  Future<void> delete(String id); // Hard Delete
+  Future<DateTime> getLastSyncTime();
+  Future<void> setLastSyncTime(DateTime time);
+}