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/2015RemoteDlg.cpp

@@ -1427,7 +1427,17 @@ VOID CMy2015RemoteDlg::CreateToolBar()
     m_ToolBar.SetButtonText(11, _TR("生成服务端"));
     m_ToolBar.SetButtonText(12, _TR("搜索"));
     m_ToolBar.SetButtonText(13, _TR("帮助"));
-    m_ToolBar.SetButtonText(14, _T("Lang/语言"));
+    // 按钮 14 "Lang/语言" 含 GBK 中文：comctl32 的 ANSI 消息按系统 ACP 解码，非中文系统会乱码，
+    // 故改用 Unicode 消息 + 显式 GBK(936)→Unicode 转换设置（与 TranslateListHeader 同法）。
+    {
+        WCHAR wLabel[64] = { 0 };
+        MultiByteToWideChar(936, 0, _T("Lang/语言"), -1, wLabel, 64);
+        TBBUTTONINFOW tbi = { 0 };
+        tbi.cbSize = sizeof(tbi);
+        tbi.dwMask = TBIF_TEXT | TBIF_BYINDEX;   // wParam 为按钮下标（与 SetButtonText(14,...) 同义）
+        tbi.pszText = wLabel;
+        ::SendMessageW(m_ToolBar.GetSafeHwnd(), TB_SETBUTTONINFOW, 14, (LPARAM)&tbi);
+    }
     m_ToolBar.SetButtonText(15, _T("MCP"));
     m_ToolBar.SetButtonText(16, _TR("连接管理"));
     m_ToolBar.SetButtonText(17, _TR("远程交谈"));