Fixed an issue where clicking the language switcher would cause a brief flash
and fail to persist the language change. The root cause was a dependency cycle
in useSettingsForm where readPersistedLanguage depended on i18n.language,
causing the initialization effect to re-run and reset state whenever the
language changed.
Changed the dependency from [i18n.language] to [i18n] since the i18n object
itself is stable and doesn't change when the language changes, while the
function can still access the current language value via closure.
e02175e68d