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/McpSettingsDlg.h

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <afxwin.h>
+#include <afxcmn.h>
+#include <vector>
+
+// 「MCP设置」配置对话框：启用 MCP / 端口 / 绑定地址 / Token。
+// 因 2015Remote.rc 为 UTF-16 编码、不宜手工编辑，参照 ZstaPickerDlg 用
+// InitModalIndirect + 内存 DLGTEMPLATE 程序化创建（见 docs/Mcp_Design.md §3.8）。
+class CMcpSettingsDlg : public CDialog
+{
+public:
+    explicit CMcpSettingsDlg(CWnd* parent = nullptr);
+
+    virtual INT_PTR DoModal();
+
+protected:
+    virtual BOOL OnInitDialog();
+    virtual void OnOK();
+
+    DECLARE_MESSAGE_MAP()
+
+private:
+    enum CtrlId {
+        IDC_MCP_ENABLE = 1001,  // 「启用 MCP」复选框
+        IDC_MCP_PORT   = 1002,  // 端口编辑框
+        IDC_MCP_BIND   = 1003,  // 绑定地址编辑框
+        IDC_MCP_TOKEN  = 1004,  // Token 编辑框
+    };
+
+    CButton m_btnEnable;
+    CStatic m_lblPort, m_lblBind, m_lblToken;
+    CEdit   m_editPort, m_editBind, m_editToken;
+    CButton m_btnOK, m_btnCancel;
+
+    std::vector<BYTE> m_Template;  // 内存 DLGTEMPLATE 字节
+
+    void LayoutControls(int cx, int cy);
+};