Add missing files

Author: jonasfj

app/lib/database/model.dart

@@ -0,0 +1,32 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:convert' show json;
+
+import 'package:gcloud/service_scope.dart' as ss;
+import 'package:json_annotation/json_annotation.dart';
+import 'package:meta/meta.dart';
+import 'package:pub_dev/shared/exceptions.dart';
+import 'package:pub_dev/task/models.dart'
+    show AbortedTokenInfo, PackageVersionStateInfo;
+import 'package:typed_sql/typed_sql.dart';
+
+export 'package:typed_sql/typed_sql.dart' hide AuthenticationException;
+
+part 'model.g.dart';
+part 'model.task.dart';
+
+/// Sets the active [database].
+void registerDatabase(Database<PrimaryDatabase> value) =>
+    ss.register(#_database, value);
+
+/// The active [Database<PrimaryDatabase>].
+Database<PrimaryDatabase> get database =>
+    ss.lookup(#_database) as Database<PrimaryDatabase>;
+
+abstract final class PrimaryDatabase extends Schema {
+  Table<Task> get tasks;
+
+  Table<TaskDependency> get taskDependencies;
+}