fix: review round 3 — a new tab keeps its account's notices, a revoked tab account lands on the default

Deep-review round 3 over main..improvement/watch-background-audio.

Account boot
- The notification history and settings, and the hints toggle, are read
  when their modules load, which in a new tab (bookmark, typed URL) is
  before BootGate pins the account: they read as nobody's, and the tab's
  first notice replaced the account's stored history (up to 100 entries)
  with a one-item list. They now read again when the tab is pinned
  (onAccountPinned, run by setActiveAccount); a notice raised before the
  pin stays, after the history.
- A tab pinned to an account still in this browser's wallet but whose
  session ended (suspended, deleted, or revoked by "log out everywhere")
  got "signed out" from /api/me while the default account was still
  signed in, and signing in again as anyone else left it there. A refused
  per-tab account now leaves the wallet, and the probe answers as the
  default, so the tab reloads onto it.

Share page (/watch)
- The password unlock is limited per viewer (link + client IP), under a
  per-link ceiling that counts only wrong passwords. Keyed on the link
  alone, ten wrong guesses every five minutes locked out every viewer,
  the ones with the password included. client_ip moves to app.ratelimit
  so the public routes can key on it.
- Its failure messages and the load-failure screen are announced
  (role=alert, the password input described by its error). The sign-in,
  passphrase, password-change and setup form errors get role=alert too.

Comments that still described removed machinery are corrected: App's
collapse flags, SettingsPanel's Save bar, ConfigPanel, authed_format_sig.

Tests: the account's history and hints across the pin; a revoked and a
suspended pinned account; the per-viewer limit and the ceiling; the
limiter's exhausted(); the share page's announced failures; a share
link's feed filters persisted. Each mutation-checked RED for its own
reason.

frontend/src/lib/activeAccount.ts

@@ -3,12 +3,30 @@
 // on it, without a circular import — the account id is a lower-level primitive than the storage
 // helpers that consume it.
 //
-// Deliberately NOT reactive: BootGate pins the account before any per-account state is read, and a
-// switch reloads the page, so nothing mounted ever sees the id change underneath it.
+// Deliberately NOT reactive: BootGate pins the account before any provider mounts, and a switch reloads
+// the page, so nothing mounted ever sees the id change underneath it. The one exception is state read at
+// module import (the notification and hints stores), which in a new tab runs before the pin: it reads
+// again through `onAccountPinned`.
 //
 // ACTIVE_ACCOUNT_KEY is duplicated here rather than imported from api.ts so this stays dependency-free.
 export const ACTIVE_ACCOUNT_KEY = "siftlode.activeAccount";
 
+// Re-readers for module-level per-account state, run each time the tab is pinned.
+const pinListeners = new Set<() => void>();
+
+export function onAccountPinned(reload: () => void): void {
+  pinListeners.add(reload);
+}
+
+export function pinActiveAccount(id: number): void {
+  try {
+    sessionStorage.setItem(ACTIVE_ACCOUNT_KEY, String(id));
+  } catch {
+    /* ignore */
+  }
+  pinListeners.forEach((reload) => reload());
+}
+
 export function activeAccountId(): number | null {
   try {
     const raw = sessionStorage.getItem(ACTIVE_ACCOUNT_KEY);