feat(webapp): showcase chat — one morning with every card type

'Morning after the deploy': report, chart, a two-revision investigation
(latest-wins), two watch confirmations, a one-shot result, a real wake with
backing watch rows (one fired, one still active for the live chip), and
docs citations. Seeded idempotently; --showcase re-seeds just this chat
over a running stand.

Author: kathiekiwi