Fix: log list header click was sorting host list (longstanding cross-talk)

ON_NOTIFY(HDN_ITEMCLICK, 0, ...) matches the inner header control's ID,
which is 0 for both m_CList_Online and m_CList_Message. So clicks on
either list's header reach OnHdnItemclickList, which always sorts the
host list by the clicked column index.

The cross-talk has existed since the initial migration commit (5a325a2).
It went unnoticed because pre-0aa7588 both lists' headers triggered the
handler in A mode and the columns happened to align (host list cols 0..2
== IP/Addr/Location, log list also has 3 cols), so log-header clicks
appeared to "sort plausibly". After 0aa7588 only the log list's A-mode
header reached the handler, surfacing the strange "click log header
re-sorts hosts" behavior.

Guard the handler by checking pNMHDR->hwndFrom against the online list's
header HWND. Log header clicks now have no effect on the host list.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/2015Remote/2015RemoteDlg.cpp

@@ -3489,10 +3489,17 @@ void CMy2015RemoteDlg::SortByColumn(int nColumn)
 
 void CMy2015RemoteDlg::OnHdnItemclickList(NMHDR* pNMHDR, LRESULT* pResult)
 {
+    *pResult = 0;
+    // ON_NOTIFY(HDN_ITEMCLICK, 0, ...) 的 ID=0 匹配的是 listview 内部 header 控件 ID，
+    // 而 m_CList_Online 和 m_CList_Message 的 header 内部 ID 都是 0，导致两边表头点击
+    // 都进这个回调（老 bug）。只处理在线主机列表的 header，避免点日志列表表头串到主机排序。
+    HWND hOnlineHeader = ListView_GetHeader(m_CList_Online.GetSafeHwnd());
+    if (pNMHDR->hwndFrom != hOnlineHeader) {
+        return;
+    }
     LPNMHEADER pNMHeader = reinterpret_cast<LPNMHEADER>(pNMHDR);
     int nColumn = pNMHeader->iItem; // 获取点击的列索引
     SortByColumn(nColumn);          // 调用排序函数
-    *pResult = 0;
 }
 
 // 虚拟列表数据回调 - 当列表需要显示某行某列的数据时调用