Drive a popover from [data-hl-popover-open]/[data-hl-popover-close] triggers. Prefers the native Popover API (showPopover/hidePopover, including light-dismiss) and falls back to toggling hidden with JS positioning, outside-click, and Escape dismissal. Triggers get aria-expanded/aria-controls wiring; open state is observable through onOpenChange/hl:open-change and controllable through the returned API.