💾 Feat(Core.Plugin): IPluginServer 接口暴露 Connections 属性

- IPluginServer 新增 Connections 属性 (IReadOnlyList<IPluginConnector>)
- PluginsServer 显式实现接口, 将内部 IPluginConnection 列表转为 IPluginConnector
- Dashboard 通过 DI 获取已连接插件函数列表, 遵循 Core/UI 分离架构

Author: StardustSeemsInk

KitX Clients/KitX Core/KitX.Core/Device/PluginsServer.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json;
 using System.Text.RegularExpressions;
 using System.Threading.Tasks;
@@ -60,6 +61,12 @@ public class PluginsServer : IPluginServer
     /// </summary>
     public IReadOnlyList<IPluginConnection> Connections => _connections.AsReadOnly();
 
+    /// <summary>
+    /// IPluginServer.Connections — returns connected plugins as IPluginConnector list
+    /// </summary>
+    IReadOnlyList<IPluginConnector> IPluginServer.Connections =>
+        _connections.Cast<IPluginConnector>().ToList().AsReadOnly();
+
     /// <summary>
     /// Event raised when a plugin connects
     /// </summary>