Feature: Add get/set clipboard buttons to remote desktop toolbar

Add two toolbar buttons — get clipboard (letter C) and set clipboard (letter P) —
after the screenshot button and before the minimize button, so clipboard sync stays
reachable in fullscreen mode where the system menu cannot be opened.

The buttons reuse the existing IDM_GET_CLIPBOARD / IDM_SET_CLIPBOARD system-menu
handlers by posting WM_SYSCOMMAND to the parent. The toolbar button count grows
from 16 to 18, and the slide/animation dimensions are widened from 640 to 720.
Letter C/P icons and Simplified-Chinese source strings ("获取剪贴板", "设置剪贴板")
are added, along with English and Traditional-Chinese translations.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/ToolbarDlg.h

@@ -39,6 +39,8 @@ public:
     CIconButton m_btnY;           // 预留按钮 Y
     CIconButton m_btnZ;           // 预留按钮 Z
     CIconButton m_btnScreenshot;
+    CIconButton m_btnGetClipboard;  // 获取剪贴板
+    CIconButton m_btnSetClipboard;  // 设置剪贴板
     CIconButton m_btnMinimize;
     CIconButton m_btnClose;
 
@@ -80,6 +82,8 @@ public:
     afx_msg void OnBnClickedY();          // 预留按钮 Y 响应函数
     afx_msg void OnBnClickedZ();          // 预留按钮 Z 响应函数
     afx_msg void OnBnClickedScreenshot();
+    afx_msg void OnBnClickedGetClipboard();
+    afx_msg void OnBnClickedSetClipboard();
     afx_msg BOOL OnEraseBkgnd(CDC* pDC);
     virtual BOOL OnInitDialog();
 };