VS popup runs over the walking scene

The pre-fight VS popup used to live on a dedicated FightDataScreen with a dark dim and nothing behind it. Walking up to an enemy now keeps the walking scene mounted: ComicVsPopup renders as a transparent-backdrop overlay when a fight is active, instead of cutting to the dark screen.

While the popup is up, the walking-scene RAF loop pauses so the hero can't keep walking and trigger another collision. The start-dialogue effect bails out when a fight is active so it doesn't replay.

Continue still dispatches fight-field. Leave (and the close X) calls leaveFight and routes back to the story map. The dedicated FightDataScreen is kept for the resume-fight reload case.