touch-action: manipulation is needed on the textarea so iOS registers
first-tap focus reliably, but it also allows pan-y — which let the
user drag the input box up off-screen with the keyboard up.
Cancelling touchmove blocks the drag without affecting tap (a tap
fires touchstart + touchend with no touchmove in between), so the
composer stays locked AND first-tap focus works.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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