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/Playlists.tsx

@@ -676,13 +676,17 @@ export default function Playlists() {
   }
 
   function playerState(id: string, status: string) {
-    api.setState(id, status).then(() => {
-      // Every cached list, not `qk.playlist(selectedId)`: the player may have been launched from a
-      // list that is no longer the selected one (see `playing`), and that list holds the row whose
-      // status just changed. Only lists actually on screen refetch.
-      qc.invalidateQueries({ queryKey: qk.playlist() });
-      qc.invalidateQueries({ queryKey: qk.feed() });
-    });
+    api
+      .setState(id, status)
+      .then(() => {
+        // Every cached list, not `qk.playlist(selectedId)`: the player may have been launched from a
+        // list that is no longer the selected one (see `playing`), and that list holds the row whose
+        // status just changed. Only lists actually on screen refetch.
+        qc.invalidateQueries({ queryKey: qk.playlist() });
+        qc.invalidateQueries({ queryKey: qk.feed() });
+      })
+      // No catch used to mean an unhandled rejection and nothing said (E11 S2b).
+      .catch((e: unknown) => notifyActionError(e, t("errors.writeFailed.videoState")));
   }
 
   // Stable identity: PlayerModal's keydown/scroll-lock effect depends on it, so a fresh closure