fix(ui): a caption never opens under a finger

On an iPad a tap's synthetic mouseenter opened the Tooltip; WebKit then took the
tap as a hover and swallowed its click, so every rail button needed two taps,
and with no mouseleave from a finger the caption stayed up. Tooltip now opens
for a mouse and a key's focus only (owner: no captions on touch).

frontend/src/components/ui/anchoredPopoverHooks.ts

@@ -62,6 +62,11 @@ export interface AnchoredPopoverOptions {
    *  preview (ui/MediaPreview): a keyboard walk down a grid would otherwise pop a panel at every stop,
    *  and a tap is the card's play. */
   pointerOnly?: boolean;
+  /** Hover mode only: never opened by a finger, still by a mouse and a key's focus. A caption over a
+   *  control (ui/Tooltip): on an iPad the tap's synthetic mouseenter showed it, WebKit then took that
+   *  first tap as a hover and swallowed its click (every rail button needed two taps), and with no
+   *  mouseleave from a finger the caption stayed up. */
+  mouseHoverOnly?: boolean;
   /** Index of the item that is currently CHOSEN, for a single-choice menu/listbox. Opening then
    *  lands the roving focus on it instead of the first item — the behaviour a "pick one of these
    *  modes" menu needs. Leave unset for action menus and multi-select toggle lists. */
@@ -166,7 +171,7 @@ export function useAnchoredPopover(opts: AnchoredPopoverOptions) {
     move: false,
     // A hover-card is a pointer affordance either way; a hover-ALSO menu must ignore touch, or the
     // synthetic mouseenter a tap emits would race the click toggle (open, then immediately shut).
-    mouseOnly: !isHover || !!opts.pointerOnly,
+    mouseOnly: !isHover || !!opts.pointerOnly || !!opts.mouseHoverOnly,
     // A submenu wants a shorter intent delay than a hover card: the pointer is already inside a
     // menu, so the "did they mean it" question is mostly answered.
     delay: opts.hoverDelay ?? (isHover ? { open: 120, close: 140 } : { open: 90, close: 120 }),