➕ Add sqlite3 dependency

lib/database/chat.dart

@@ -0,0 +1,26 @@
+import 'package:drift/drift.dart';
+import 'package:surface/types/chat.dart';
+
+class SnLocalChatChannel extends Table {
+  IntColumn get id => integer().autoIncrement()();
+
+  BlobColumn get content => blob().map(TypeConverter.jsonb(
+    fromJson: (json) => SnChannel.fromJson(json as Map<String, Object?>),
+    toJson: (pref) => pref.toJson(),
+  ))();
+
+  DateTimeColumn get createdAt => dateTime().withDefault(currentDateAndTime)();
+}
+
+class SnLocalChatMessage extends Table {
+  IntColumn get id => integer().autoIncrement()();
+
+  IntColumn get channelId => integer()();
+
+  BlobColumn get content => blob().map( TypeConverter.jsonb(
+    fromJson: (json) => SnChatMessage.fromJson(json as Map<String, Object?>),
+    toJson: (pref) => pref.toJson(),
+  ))();
+
+  DateTimeColumn get createdAt => dateTime().withDefault(currentDateAndTime)();
+}