Fix: Decode GBK dialog/toolbar text on non-Chinese systems

MBCS dialog templates are decoded with the system ANSI code page, so on
non-Chinese systems the GBK template strings turn into "?" before
TranslateDialog can read them. Set those strings explicitly in OnInitDialog
(PluginSettings save/close, the three Advanced dialogs, the file-manager
search buttons/checkboxes, and Trigger Settings) so they are re-decoded
with the thread locale. Also fix the language-selection dialog and the
toolbar "Lang/语言" button: the language dialog's template is built as
WCHAR strings but created through the ANSI path, so its title, label, and
buttons are set explicitly in OnInitDialog (AppendString stays on CP_ACP),
with the title looked up via _TR("切换语言") and set through SetWindowTextW
after an explicit GBK conversion; new en_US ("Switch Language") and zh_TW
("切換語言") translations accompany it. The toolbar button is set through
the Unicode TB_SETBUTTONINFOW message after an explicit GBK conversion. Add
en_US/zh_TW translations for the experimental-features context menu items.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/PluginSettingsDlg.cpp

@@ -102,6 +102,10 @@ void CPluginSettingsDlg::InitListCtrl()
     GetDlgItem(IDC_STATIC_PLUGIN_INTERVAL)->SetWindowText(_TR("间隔(秒):"));
     GetDlgItem(IDC_STATIC_PLUGIN_COUNTER)->SetWindowText(_TR("最大次数:"));
     SetWindowText(_TR("插件设置"));
+
+    // 按钮文字来自对话框模板，非中文系统上会被系统 ACP 转成 "??"，须显式设置（参照 NotifySettingsDlg）
+    SetDlgItemText(IDC_BTN_SAVE, _TR("保存"));
+    SetDlgItemText(IDOK, _TR("关闭"));
 }
 
 void CPluginSettingsDlg::LoadPluginsToList()