Row Actions Menu

The component is self-contained: one file, no dependencies, the palette in --vibeui-datagrid-028-*. A client component: useState holds the identifier of the open row, a ref holds the trigger buttons, and useId gives stable panel ids for aria-controls. The menu is built on the keyboard model: the down arrow on the button opens it, the arrows walk the items, Home and End jump to the ends, and Escape closes it and returns focus to the button — without that return the focus flies to the top of the page. The markup is honest: a list with role=menu and buttons with role=menuitem. The destructive item is separated by a line and marked with a colour together with the word "Delete": colour alone is not a warning. The theme comes from the surrounding color-scheme through light-dark(): by default the table lays no panel under itself, it sits directly on the page background and darkens along with it, and the opaque background is left on the menu — a popup layer has to cover the rows.