Fixes half of #70 - the long-tap/count-picker interaction.
Pointer Events (onPointerDown/Up/Cancel) only shipped in Safari 13/iOS
13. The same class of old-enough-WebKit kiosk device #66/#68 are
already about doesn't fire them at all, so the long-press timer never
starts there even though plain clicks (universally supported) keep
working - which matches the report exactly: add-one-by-tapping works
on the tablet, the long-press count picker doesn't, and both work fine
on a laptop's modern browser.
Added onTouchStart/onTouchEnd/onTouchCancel alongside the existing
pointer handlers, wired to the same start/cancel functions - safe on
browsers that fire both pointer and touch events for one touch, since
starting/cancelling the timer is already idempotent.
Not touching the second half of the report (negative amounts for
cart-only drinks) - genuinely ambiguous relayed text with several
plausible readings that imply different UI, asked mara for
clarification on the issue instead of guessing.
pnpm --filter client typecheck and build both clean.
0ae25ecab7