Feature: Add "Unban IP" to log message context menu in main dialog

- Add "Unban IP" menu item to the log message list (m_CList_Message)
  right-click context menu, performing two actions on the extracted IP:
  1. Remove the IP from the IPBlacklist singleton and persist to config
  2. Scan the entire history host list (m_ClientMap->GetAll()) for all
     clients matching the IP with AUTH_FORBIDDEN status, and restore
     them to UNAUTHORIZED (0) — requiring re-authorization for safety
- Reuses ExtractFirstIPFromMessage() for dependency-free IPv4 parsing
- Handles the case where an IP is not in the blacklist and has no
  matching forbidden clients with a clear "no action needed" message
- Menu item is grayed out when no log entry is selected
- Sync en_US / zh_TW language files with new translation strings

Co-Authored-By: DeepSeek V4 Pro

server/2015Remote/2015RemoteDlg.h

@@ -566,6 +566,7 @@ public:
     afx_msg void OnMsglogSearch();
     afx_msg void OnMsglogLoginNotify();
     afx_msg void OnMsglogBanIP();
+    afx_msg void OnMsglogUnbanIP();
     afx_msg void OnOnlineAddWatch();
     afx_msg void OnNMCustomdrawOnline(NMHDR* pNMHDR, LRESULT* pResult);
     afx_msg void OnOnlineRunAsAdmin();