Feat: Per-client TLS transport toggle (TLS column + remote enable/disable)

Add a per-client TLS transport toggle controlled from the server, using the
presence of the client's trust-anchor certificate in the registry as the
single source of truth (no separate tls_enable flag).

- Client reports its TLS status via a new RES_TLS token (cert present -> 1)
  appended to LOGIN_INFOR's reserved field.
- Server online list gains a "TLS" column after the permission column.
- The "experimental features" right-click menu gains "TLS传输" / "取消TLS"
  with confirmation and a guard that prompts (instead of sending) when the
  server has no TLS certificate ready.
- New COMMAND_TLS_ENABLE / COMMAND_TLS_DISABLE (166/167): the server pushes
  its cert PEM into the client registry settings\tls_cert (enable) or deletes
  it (disable). The client picks this up on next startup via the existing
  ReadTrustAnchor logic, so the switch is non-live by design.
- Icons and en_US/zh_TW/de_DE translations for the new menu items.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/lang/zh_TW.ini

@@ -2087,3 +2087,9 @@ TLS֤
 TLS 配置已保存。=TLS 設定已儲存。
 改动对新建连接即时生效。=變更對新連線即時生效。
 证书/私钥加载失败，加密功能未生效。请检查文件路径与格式（证书 PEM、私钥 PKCS#8）。=憑證/私鑰載入失敗，加密功能未生效。請檢查檔案路徑與格式（憑證 PEM、私鑰 PKCS#8）。
+TLS传输=TLS 傳輸
+取消TLS=停用 TLS
+确定对选中主机启用 TLS 传输吗？（客户端下次启动生效）=確定對選取主機啟用 TLS 傳輸嗎？（用戶端下次啟動生效）
+确定取消选中主机的 TLS 传输吗？（客户端下次启动生效）=確定取消選取主機的 TLS 傳輸嗎？（用戶端下次啟動生效）
+服务端未启用 TLS 证书，无法切换客户端 TLS 传输=伺服器未啟用 TLS 憑證，無法切換用戶端 TLS 傳輸
+读取服务端 TLS 证书失败，无法下发=讀取伺服器 TLS 憑證失敗，無法下發