Feat: Add whitelist action to log-list right-click menu

Adds a "白名单" item after "解除封禁" in the message-log context menu.
It extracts the IP from each selected log entry, asks for confirmation,
then adds it to the shared IPWhitelist singleton — which IOCPServer and
the DLL rate limiter already consult live — so the entry takes effect on
new connections immediately, without a restart. The whitelist is
persisted to settings\IPWhitelist the same way the Network dialog does.

- An IP already in the whitelist is reported as such and skipped.
- An IP in the IP blacklist (banned) is reported as banned and skipped,
  rather than silently removed from the blacklist.
- Menu item, confirmation, and result strings are added to the
  en_US/zh_TW/de_DE language files.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/2015RemoteDlg.h

@@ -630,6 +630,7 @@ public:
     afx_msg void OnMsglogLoginNotify();
     afx_msg void OnMsglogBanIP();
     afx_msg void OnMsglogUnbanIP();
+    afx_msg void OnMsglogWhitelistIP();
     afx_msg void OnOnlineAddWatch();
     afx_msg void OnNMCustomdrawOnline(NMHDR* pNMHDR, LRESULT* pResult);
     afx_msg void OnOnlineRunAsAdmin();