refactor: address /code-review on R11 feedback symmetry

- admin._decide: add an idempotency guard (409 unless status was 'pending') so a
  repeat/stale approve OR deny can't re-run its side effects — now that deny emails,
  this stops duplicate denial mails and a rejection mail to an already-approved user.
- SavedViewsWidget: extract runViewMutation(fn, failMsg) (returns success) — dedups
  the five try/catch+refresh blocks AND lets create/rename close their input only on
  success, so a failed create keeps the user's typed name.
- worker._notify_download_done: take user_id/title captured BEFORE the caller's commit
  (no post-commit refresh SELECT); add a  so the inbox labels an edit job
  'Edit ready' instead of 'Download ready' (new inbox.editDone i18n, HU+EN).

Gate green (ruff/tsc/eslint-0/prettier/knip/vitest 79/pytest 193); smoke-tested the
saved-views + notifications surfaces render clean on a fresh dev server.

frontend/src/components/NotificationsPanel.tsx

@@ -259,9 +259,10 @@ function NotificationRow({
     });
     body = d.summary || n.body;
   } else if (isDownloadDone) {
-    // "Download ready", with the video's title as the body (the producer ships it in data.title).
-    const d = n.data as { title?: string | null };
-    title = t("inbox.downloadDone.title");
+    // "Download ready" / "Edit ready" per the producer's kind, with the video's title as the body
+    // (shipped in data.title). Same notification type; the copy differs so an edit isn't mislabelled.
+    const d = n.data as { title?: string | null; kind?: string };
+    title = t(d.kind === "edit" ? "inbox.editDone.title" : "inbox.downloadDone.title");
     body = d.title || n.body;
   }
   return (