fix(ui): a write that fails says what failed and why, wherever it fails

`req` opens its blocking dialog for 400/409/422/5xx only. A 403/404/429 was left to the caller and a
502-504 or lost connection got just the self-clearing connection notice, so 34 mutations without a
reporting onError and 15 direct api writes with a bare or missing catch failed in silence: a hidden
channel that snapped back, a share link that never revoked, a confirmed account delete that ended
with nothing said.

- lib/queryClient: one MutationCache reporter. react-query awaits it BEFORE the mutation's own
  onError, so it waits a task and skips a failure the site already reported; the toast title comes
  from `meta.failTitle`, `meta.errorShownInline` opts out.
- notifyActionError: title names WHAT failed, the line under it says WHY (`failureReason`: a
  structured localized detail, else the status). It marks the error reported (`markReported`), so
  nothing reports one failure twice; `notifyKnownFailure` for a site's own specific sentence.
- Every silent site named (45 new HU/EN titles, 4 reasons). Stale "the global dialog shows it"
  comments corrected on the job actions, channel block, Plex sync, cookies, download enqueue,
  account delete and usePref.
- Channels passed the tag hook's channel id to the reporter as the error; the tag and priority hooks
  now report themselves, with the real error.
- A contract test keeps every useMutation naming its failure; CLAUDE.md gains the pattern row.
- history.dom.test: the "navigates only once the entries are back" assertion raced an async act's
  macrotask flush (1 in 5 runs); it now asserts from a later popstate listener.

frontend/src/components/accountPanel.dom.test.tsx

@@ -87,11 +87,13 @@ beforeEach(() => {
 });
 afterEach(cleanup);
 
+// What each error toast names: its title when it has one (a failure reported with its reason under
+// it — E11 S2b), else the specific sentence (the no-mail case).
 const errorMessages = () =>
   notifyMock.mock.calls
-    .map(([a]) => a as { level?: string; message?: string })
+    .map(([a]) => a as { level?: string; title?: string; message?: string })
     .filter((a) => a.level === "error")
-    .map((a) => a.message);
+    .map((a) => a.title ?? a.message);
 
 describe("the account panel reports a refused recovery action", () => {
   it("says the link could not be minted instead of leaving the button inert", async () => {