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/ui/Button.tsx

@@ -119,7 +119,12 @@ interface ButtonOwnProps extends ButtonHTMLAttributes<HTMLButtonElement> {
 // use it for the tooltip that IS the name.
 type NamedSomehow = { label: string } | { "aria-label": string } | { title: string };
 type TextlessButton = ({ iconOnly: true } | { size: "icon" | "icon-sm" }) & NamedSomehow;
-type TextfulButton = { iconOnly?: false; size?: Exclude<ButtonSize, "icon" | "icon-sm"> };
+// …and a button of any other size must actually HAVE text, or be named: `<Button icon={x} />` with
+// no children and no size typechecked into a nameless button (E10 review).
+type TextfulButton = { iconOnly?: false; size?: Exclude<ButtonSize, "icon" | "icon-sm"> } & (
+  | { children: ReactNode }
+  | NamedSomehow
+);
 export type ButtonProps = ButtonOwnProps & (TextlessButton | TextfulButton);
 
 /** The shared action button. `type` defaults to "button" so it never accidentally submits a form. */