The remove buttons on a collection's cards were revealed only on
hover / focus-within (opacity 0 → 1), so on touch they were invisible and
undiscoverable. Show them persistently at the 640px breakpoint and enlarge
the hit area from 24px to 32px (kept below the full 44px floor because the
button floats over a 4-up cover thumbnail).
Test pins the CSS contract (jsdom can't evaluate @media): the mobile block
makes `.remove` opaque.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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