Redesign research card and composer

One anatomy for every stage (status row, question/report title, callout,
outline footer button), a live progress track below the card, opacity-only
crossfades and grid-row folds, a borderless composer with inset controls,
a 450px width cap, and a new btn-outline tier.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>