A turn the provider ends at its per-request output cap previously produced
no visible sign in the Web chat flow: only error-kind turn/end events built
a conversation node, so the truncated answer read as a normal completion.
Add a turn-max-tokens conversation node Definition over the durable
turn/end event, a warning-styled localized notice row distinct from
turn-error, a fixture max-tokens sample turn, and an assembled keyless
snapshot pinning the dot state, title, and hint.
Closes#1522
creatixchu
e4ca03cb85