fix(ui): stable shelf-card menu triggers, a named Button by type, true layout comments

- Home's rail handed each card a fresh `() => menu.triggerProps(c)` per
  render, defeating memo(VideoCard) on every tile whenever the menu's own
  state changed. `useItemTriggers` (ui/useContextMenu) keeps one trigger per
  item, index-aligned; tested for identity across renders.
- The Button accessible-name union had one hole: `<Button icon={…} />` with
  no children and no size typechecked into a nameless button. A textful
  button now needs children or a name; pinned with @ts-expect-error.
- comfortPin's header said the pin belongs "on every card and row", which
  the code never meant (an episode, a season, a person are not pin kinds).
  It now says what is pinnable — and the show page's Related strip, whose
  shows ARE pinnable, gets the pin menu it was missing (and a rem width).
- gridColumns / feedView / VirtualGrid claimed layouts 1024–2560 are
  "byte-identical" under the column cap; the small cards are capped at 2560
  with the filter rail collapsed. The comments say so.

frontend/src/components/plexCards.tsx

@@ -412,9 +412,12 @@ export function CastStrip({
 export function RelatedStrip({
   related,
   onOpen,
+  menuProps,
 }: {
   related: PlexCard[];
   onOpen: (id: string) => void;
+  /** The comfort-pin context menu's trigger (a related show is pinnable like any poster). */
+  menuProps?: (c: PlexCard) => Record<string, unknown>;
 }) {
   const { t } = useTranslation();
   return (
@@ -428,8 +431,9 @@ export function RelatedStrip({
           <button
             key={r.id}
             {...navItemAttrs(i)}
+            {...menuProps?.(r)}
             onClick={() => onOpen(r.id)}
-            className="group w-[130px] shrink-0 text-left"
+            className="group w-32.5 shrink-0 text-left"
           >
             <div className="glass-card glass-hover relative aspect-2/3 rounded-xl overflow-hidden transition-all duration-200">
               <img