feat(design): a video's one action list (C1) — the card's "…", the menu holds the rest (E28 S3e1)

- useContextMenu gains buttonProps (a row's visible "…" opens the same menu under the button; a
  second press closes it) and anchor (the element the menu came from, for a panel a row opens).
- ui/MoreButton; ActionMenu rows can run inGesture (a clipboard write inside the click, Safari).
- useVideoActions: one builder for a video's menu (play / restart, channel, watched, save, add to
  playlist, download, details, copy title / link, hide, reset, pin), composed by the feed and by
  Home's rails; the playlists and details panels open anchored beside the card (VideoFollowUp).
- The card keeps watched / save / add to playlist and the "…": on the picture on hover (the
  duration steps aside), in the rows' action column; on touch only a 44px "…" beside the title.
  Download, hide, reset and the hover info card leave the card.
- The title is selectable: a click ending a selection neither plays nor follows the link.
- DESIGN.md: how C1 is built + the log row.

frontend/src/components/Home.tsx

@@ -38,6 +38,7 @@ import { useContextMenu, useItemTriggers } from "./ui/useContextMenu";
 import SegmentedToggle from "./ui/SegmentedToggle";
 import { LoadingState, StateMessage } from "./ui/QueryState";
 import VideoCard from "./VideoCard";
+import { useVideoActions } from "./useVideoActions";
 import { PlexPosterCard } from "./plexCards";
 import { useNavigationActions } from "./navigationContext";
 import { usePlexActions } from "./plexContext";
@@ -122,6 +123,9 @@ function Rail({
   // the scroll, and because these rows are keyboard-reachable (Shift+F10) for free.
   const menu = useContextMenu<DiscoverCard>();
   const pin = useComfortPin(menu.open);
+  // A video tile's own action list (E28 C1), the same one the feed's menu shows; the rail keeps its
+  // Play row (it resolves `next`) and its shelf rows around it.
+  const videoActions = useVideoActions({ onState, onToggleSave }, menu.open);
   const target = menu.target;
   const shelfIdx = target?.pin_id != null ? cards.findIndex((c) => c.pin_id === target.pin_id) : -1;
   const items: ActionMenuItem[] = !target
@@ -137,6 +141,11 @@ function Rail({
           disabled: !(target.next ?? target).video && !(target.next ?? target).plex,
           onSelect: () => onPlay(target),
         },
+        ...(target.video
+          ? videoActions
+              .items(target.video, menu.anchor, { pin: false })
+              .map((it, i) => (i === 0 ? { ...it, separatorBefore: true } : it))
+          : []),
         ...(onMove && target.pin_id != null
           ? [
               ...SHELF_MOVES.map(([to, key, Icon], i) => ({
@@ -170,6 +179,7 @@ function Rail({
   // One stable trigger per card (the menu acts on the unified card, not the `Video`/`PlexCard` the
   // card component holds) — a fresh lambda per render defeated `memo(VideoCard)` on every tile.
   const menuFor = useItemTriggers(cards, menu.triggerProps);
+  const buttonFor = useItemTriggers(cards, menu.buttonProps);
 
   // An empty rail says why it is empty rather than vanishing: a shelf that silently disappears when
   // you have not pinned anything teaches nothing about how to fill it.
@@ -204,6 +214,8 @@ function Rail({
                 onToggleSave={onToggleSave}
                 onOpen={(v, startAt) => onPlay({ ...c, video: v }, startAt)}
                 menuProps={menuFor[i]}
+                menuButtonProps={buttonFor[i]}
+                menuOpen={menu.open && menu.target === c}
               />
             ) : c.plex ? (
               <PlexPosterCard
@@ -221,6 +233,7 @@ function Rail({
         ))}
       </Carousel>
       <ContextMenu menu={menu} ariaLabel={ariaLabel} items={items} />
+      {videoActions.panel}
     </section>
   );
 }