Settings: language and theme, kept in the app

Appearance in Settings chooses the language (the system's, or one of the nine the app has;
the window opens again in it, its replies and shells let go first) and the theme (the
account's, or Moria or Shire, drawn at once and the window painted in it). Kept in
localStorage on this computer: /api/v2 has no PATCH /me for either yet, so the account's
own stay as they are. i18n.js reads the choice and carries each language's own name from
the server's catalogue. Tests E5.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ui/js/bridge.js

@@ -125,3 +125,10 @@ export async function openTerminal(target, cols, rows, { onOutput, onControl, on
 export function openLink(url) {
   return invoke("open_external", { url }).catch(() => {})
 }
+
+/** Let go of every reply followed and every shell open (the page is about to load again). */
+export function letGoAll() {
+  const ids = [...followers.keys()].map((id) => invoke("stream_close", { id }))
+  const shells = [...terminals.keys()].map((id) => invoke("terminal_close", { id }))
+  return Promise.allSettled([...ids, ...shells])
+}