Keep shoppers in place when they close the video player

Closing the fullscreen player restores shoppers to the same spot on the page, including when the store’s cart drawer opens right afterward. The page no longer jumps to the top.

• Stay on the shop page. If the page URL already ends in `#player` when a shopper opens the player, closing it clears the `#player` part without taking them to the previous page.
• Close only once. If Escape or the player’s close button is pressed more than once, the player closes only once.