Phase 1: data models and local storage service

- Add Models: Category, ToolItem (IsValid runtime-only, not stored), AppConfig

- Add Services: IDataService + JsonDataService (JSON load/save)

- Path validation on Load(): File.Exists check, logs warning for missing paths

- Startup: auto-calls dataService.Load() to load config

PersonalToolBox/App.xaml.cs

@@ -20,6 +20,10 @@ public partial class App : Application
         ConfigureServices(services);
         Services = services.BuildServiceProvider();
 
+        // 启动时加载配置文件（含路径验证与容错）
+        var dataService = Services.GetRequiredService<IDataService>();
+        dataService.Load();
+
         var mainWindow = Services.GetRequiredService<MainWindow>();
         mainWindow.Show();
     }
@@ -32,6 +36,9 @@ public partial class App : Application
         // 日志服务
         services.AddSingleton<ILogService, LogService>();
 
+        // 数据持久化服务
+        services.AddSingleton<IDataService, JsonDataService>();
+
         // 主窗口
         services.AddSingleton<MainWindow>();
     }