A phone has no hover to preview a card, so tapping now opens a magnified,
fully-readable view with the actions that fit it instead of acting blind:
- Shop card: tap to see it big, then Buy (or read it even when unaffordable).
- Your deck card: tap to see it big, then Sell it, or Select to enter a
bulk-selection mode where taps toggle pets (no magnify) and the action bar
offers Sell / Triple / Cancel.
Desktop keeps click-to-buy and click-to-select unchanged; the new behavior is
gated on a max-width:600px media query via a small useMediaQuery hook.
