Feature: Add MCP (Model Context Protocol) server integration

Add an optional MCP server (JSON-RPC 2.0 over Streamable HTTP) exposing
an online-host listing tool, protected by a Bearer token. Disabled by
default; configured via a new "Extensions > MCP Settings" dialog.

- McpServer: httplib + JSON-RPC 2.0 dispatch (initialize/ping/tools/list/tools/call)
- McpSettingsDlg: runtime-created dialog for enable/port/bind/token
- HostJson: extract single-host JSON serialization shared with WebService
- FRP: expose MCP port (union with listening/Web ports) when bound to 0.0.0.0
- i18n: en_US / zh_TW translations

Co-Authored-By: deepseek-v4-pro

server/2015Remote/McpServer.h

@@ -0,0 +1,58 @@
+#pragma once
+
+#include <Windows.h>
+#include <string>
+#include <thread>
+#include <atomic>
+#include <chrono>
+
+// httplib 与 Windows 头部的 min/max 宏冲突，按 file_server.h 的既有约定处理。
+#undef min
+#undef max
+#include "httplib.h"
+#ifndef max
+#define max(a,b) (((a) > (b)) ? (a) : (b))
+#endif
+#ifndef min
+#define min(a,b) (((a) < (b)) ? (a) : (b))
+#endif
+
+#pragma comment(lib, "ws2_32.lib")
+
+class CMy2015RemoteDlg;
+
+// MCP (Model Context Protocol) 服务端：httplib 封装 + JSON-RPC 2.0 分发 + 静态 token 校验。
+// 与 CWebService 平级、互不依赖；默认禁用，经「扩展 → MCP设置」开启后监听
+// （默认 127.0.0.1:6544，仅本机回环）。见 docs/Mcp_Design.md。
+class CMcpServer {
+public:
+    static CMcpServer& Instance();
+
+    void SetParentDlg(CMy2015RemoteDlg* pDlg) { m_parent = pDlg; }
+    void SetToken(const std::string& token) { m_token = token; }
+
+    bool Start(const std::string& bind, int port);
+    void Stop();
+    bool IsRunning() const { return m_running.load(); }
+
+private:
+    CMcpServer();
+    ~CMcpServer();
+    CMcpServer(const CMcpServer&) = delete;
+    CMcpServer& operator=(const CMcpServer&) = delete;
+
+    // POST /mcp 处理器：token 校验 + JSON-RPC 分发。
+    void HandleMcp(const httplib::Request& req, httplib::Response& res);
+
+    httplib::Server    m_server;
+    std::thread        m_thread;
+    std::atomic<bool>  m_running{false};
+    std::string        m_token;
+    CMy2015RemoteDlg*  m_parent = nullptr;
+};
+
+// 全局访问器（仿 WebService()，见 WebService.h 末尾）
+inline CMcpServer& McpServer() { return CMcpServer::Instance(); }
+
+// 生成 32 hex（128-bit）随机 token；供运行时兜底与「MCP设置」对话框预填复用。
+std::string GenerateRandomToken();