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/ui/ActionMenu.tsx

@@ -58,6 +58,10 @@ interface ActionItem extends MenuItemBase {
   onSelect: () => void;
   /** Destructive action: painted in the danger colour, like the outline-danger buttons. */
   danger?: boolean;
+  /** Run INSIDE the click, then close — for a clipboard write, which Safari allows only within the
+   *  user's gesture (a task later, as `closeThenAct` runs every other row, it is refused). Only for
+   *  an action that opens nothing and moves no focus: that is what the deferral exists for. */
+  inGesture?: boolean;
   items?: never;
 }
 
@@ -100,7 +104,11 @@ export function MenuItemList({
               label={it.label}
               title={it.title}
               // Any row may open a dialog (a confirm), so every row closes first — see closeThenAct.
-              onSelect={() => closeThenAct(onClose, it.onSelect)}
+              onSelect={() => {
+                if (!it.inGesture) return closeThenAct(onClose, it.onSelect);
+                it.onSelect();
+                onClose();
+              }}
               className={`${ROW}${it.danger ? " text-danger" : ""}`}
             >
               {it.icon && (