Fix weird sqlcipher factor inheritance

Author: simolus3

packages/powersync_core/lib/web.dart

@@ -4,3 +4,7 @@ library;
 export 'src/web/worker_utils.dart' show PowerSyncAdditionalOpenOptions;
 export 'package:sqlite_async/sqlite3_web.dart';
 export 'package:sqlite_async/web.dart';
+
+import 'src/open_factory/web/web_open_factory.dart';
+
+typedef PowerSyncWebOpenFactory = PowerSyncOpenFactory;

packages/powersync_sqlcipher/lib/powersync.dart

@@ -14,16 +14,14 @@ import 'src/stub.dart'
 
 /// A factory for opening a database with SQLCipher encryption.
 /// An encryption [key] is required to open the database.
-abstract base class PowerSyncSQLCipherOpenFactory extends PowerSyncOpenFactory {
-  PowerSyncSQLCipherOpenFactory.internal(
-      {required super.path, required this.key, super.sqliteOptions});
-
+abstract interface class PowerSyncSQLCipherOpenFactory
+    extends PowerSyncOpenFactory {
   factory PowerSyncSQLCipherOpenFactory(
       {required String path,
       required String key,
       SqliteOptions sqliteOptions = powerSyncDefaultSqliteOptions}) {
     return cipherFactory(path: path, key: key, options: sqliteOptions);
   }
 
-  final String key;
+  String get key;
 }

packages/powersync_sqlcipher/lib/src/sqlcipher.dart

@@ -5,12 +5,16 @@ import 'package:sqlcipher_flutter_libs/sqlcipher_flutter_libs.dart';
 
 import '../powersync.dart';
 
-final class _NativeCipherOpenFactory extends PowerSyncSQLCipherOpenFactory {
+final class _NativeCipherOpenFactory extends PowerSyncOpenFactory
+    implements PowerSyncSQLCipherOpenFactory {
+  @override
+  final String key;
+
   _NativeCipherOpenFactory({
     required super.path,
-    required super.key,
+    required this.key,
     super.sqliteOptions,
-  }) : super.internal();
+  });
 
   @override
   List<String> pragmaStatements(SqliteOpenOptions options) {

packages/powersync_sqlcipher/lib/src/web_encryption.dart

@@ -3,13 +3,16 @@ import 'package:powersync_core/web.dart';
 
 import '../powersync.dart';
 
-final class _WebEncryptionFactory extends PowerSyncSQLCipherOpenFactory
-    with WebSqliteOpenFactory {
+final class _WebEncryptionFactory extends PowerSyncWebOpenFactory
+    implements PowerSyncSQLCipherOpenFactory {
+  @override
+  final String key;
+
   _WebEncryptionFactory({
     required super.path,
-    required super.key,
+    required this.key,
     super.sqliteOptions,
-  }) : super.internal();
+  });
 
   @override
   List<String> pragmaStatements(SqliteOpenOptions options) {