feat(design): the channel menu's Tags and Priority submenus (C1, E28 S3e3b)

Tags A-Z as in-place checks (the menu stays open for the next); Priority
as the fixed steps 10 5 3 2 1 0, an off-scale current value ticked in its
place. A pick re-sorts the list at once, moving only that row
(placeByPriority, the server's order), and the table / card pager and
the focus follow it (DataTable and useCardPager take a reveal seq,
listNav.focusNavItem lands on the row's own "…", a virtualized card
revealed first). ActionMenu rows take check: many | one. The menu reads
the row fresh from the cache and keys its target by id.

frontend/src/components/ui/DataTable.tsx

@@ -69,6 +69,7 @@ export default function DataTable<T>({
   onFiltersChange,
   fixedLayout = false,
   keyboardNav = false,
+  reveal,
 }: {
   rows: T[];
   columns: Column<T>[];
@@ -121,6 +122,10 @@ export default function DataTable<T>({
   // Enter clicks the element a column's render marks `data-nav-open` (the channel name). Both row
   // shapes register; listNav walks only the one on screen, so the hidden copy is never a stop.
   keyboardNav?: boolean;
+  // Follow a row the caller just MOVED (a channel re-sorted by the priority its menu set): each new
+  // `seq` turns to the page that now holds the row `key`. Focus is the caller's (it knows which of
+  // the row's controls it came from); the page is the table's, so it is decided here.
+  reveal?: { key: string; seq: number } | null;
 }) {
   const { t } = useTranslation();
   const initial = loadPersist(persistKey);
@@ -208,6 +213,15 @@ export default function DataTable<T>({
   const allRows = size <= 0;
   const totalPages = allRows ? 1 : Math.max(1, Math.ceil(sorted.length / size));
   const safePage = Math.min(page, totalPages - 1);
+  // Adjusted DURING render against the last seq seen (the house's key-change reset), so the frame
+  // that re-sorted the row already shows its new page. Seeded with the mount's seq: arriving with a
+  // stale reveal must not move a page nobody asked to move.
+  const [revealSeen, setRevealSeen] = useState(reveal?.seq);
+  if (reveal && reveal.seq !== revealSeen) {
+    setRevealSeen(reveal.seq);
+    const at = sorted.findIndex((row) => rowKey(row) === reveal.key);
+    if (at >= 0 && !allRows) setPage(Math.floor(at / size));
+  }
   const paged = allRows ? sorted : sorted.slice(safePage * size, safePage * size + size);
 
   function toggleSort(key: string) {