{{/* lang_switcher — the language switcher, shared by index.html (sidebar footer, next to the theme toggle) and every auth.html page. Expects a dict with: CSRFToken — the page's CSRF token Lang — the page's current locale code ("en", "fr", …) Next — where SetLanguage should redirect back to after the POST; each call site passes its own page path since, unlike ConversationID for the theme toggle, there's no single field every page that includes this partial has in common. Deliberately plain {{ end }}