From tablet up, a Quest-log or Regular dinner is dragged from desktop's
right panel or tablet's Quest-log strip onto a day of the week to swap it
in. Pointer events with capture: the source becomes a dashed ghost at 55%
opacity, a copy floats with shadow-lg at -3deg, and the day under the
pointer shows a dashed 2.5 px grape border on grape-100 with "Drop to swap /
Replaces {dinner}". Letting go over a day calls useSwapDay's mutate, so the
swap is optimistic and rolls back with the existing error; anywhere else, a
pointer cancel or Escape cancels with no request.
Keyboard alternative: Enter or Space picks a row up onto Monday, the arrow
keys choose the day, Enter drops (moving focus to that day's swap button),
Escape or leaving the row cancels. Each step is announced in a polite live
region. No drag starts while a swap of the week is pending, nor for a
dinner already this week, matching the swap sheet. Mobile is unchanged.
Task: 5c2842a8-5ac1-4141-9575-c0f461d90c3e
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>