fix(ui): simplify login and suppress pointer focus ring on locale select

frontend/src/shell/host/FullHeader.tsx

@@ -12,6 +12,7 @@ export function FullHeader({ onLogout }: { onLogout?: () => Promise<void> }) {
   const user = useAuthUser();
   const [fullscreenPending, setFullscreenPending] = useState(false);
   const [logoutPending, setLogoutPending] = useState(false);
+  const [languagePointerFocus, setLanguagePointerFocus] = useState(false);
   const [error, setError] = useState<string>();
   if (shell?.mode !== "full") return null;
   const fullscreenLabel = shell.fullscreen ? t("Exit fullscreen") : t("Enter fullscreen");
@@ -41,7 +42,12 @@ export function FullHeader({ onLogout }: { onLogout?: () => Promise<void> }) {
       <span className="thot-full-header__brand">Thoth<span>II</span></span>
       <div className="thot-full-header__controls">
         <label className="sr-only" htmlFor="thot-ui-language">{t("Interface language")}</label>
-        <select id="thot-ui-language" className="thot-shell-select" value={shell.locale} onChange={event => shell.changeLocale(event.target.value)}>
+        <select id="thot-ui-language" className="thot-shell-select" value={shell.locale}
+          data-pointer-focus={languagePointerFocus || undefined}
+          onPointerDown={() => setLanguagePointerFocus(true)}
+          onKeyDown={event => { if (event.key !== "Escape") setLanguagePointerFocus(false); }}
+          onBlur={() => setLanguagePointerFocus(false)}
+          onChange={event => shell.changeLocale(event.target.value)}>
           {availableLocales.map(({ code, name }) => <option key={code} value={code} lang={code}>{name}</option>)}
         </select>
         <Button variant="ghost" size="icon" aria-label={shell.theme === "light" ? t("Use dark theme") : t("Use light theme")}