Attributing listener-attaching components per widget found the same anti-pattern the
shared board context menu already fixed once, still present in list widgets:
interact nodes fibers kind / which components
340 2951 8387 mediaReleases
UnstyledButton x90 TooltipFloating x80 Popover x80
PopoverDropdown x80 PopoverTarget x10
171 251 1195 calendar
UnstyledButton x45 Popover x42 PopoverDropdown x42
PopoverTarget x42
46 264 898 downloads
Tooltip x30
Mantine mounts a TooltipFloating's Popover machinery even when the tooltip is disabled, so
wrapping every card unconditionally produced 80 TooltipFloating, 80 Popover and 80
PopoverDropdown components - 240 of this widget's 340 listener-attaching components - for
tooltips that only show on hover, on cards that are 91% off-screen.
Deciding before rendering means a card with no description, or with the option off, mounts
none of it. Behaviour is unchanged for cards that do have a description.
Also extends measure-widget-cost.mts to count these components per widget, which is what
found it. The board's 8,165 event listeners were never attributable before; now they are.
Not yet measured: the listener reduction depends on how many releases carry a description,
which is integration data. The mechanism is certain (the components are simply not created)
but the size of the win on a given board is not, and calendar's 42 Popovers and downloads'
30 Tooltips are untouched. Tracked in docs/perf/NEXT-STEPS.md.