Consume the card:'web' result view (structured sources + answer for search, the
URL and HTTP status for fetch) the web backend PR added. WebBlock
(ui-primitives) draws both kinds via the kind discriminant: a citation list of
safe external links (the MarkdownText protocol allowlist, title-or-hostname
label), a truncation indicator, a height cap matching TerminalBlock; a fetch
summary for the other kind. web-card-model is the single resultView derivation;
a keyed WebRow registers under web_search and web_fetch with the card resident
under its summary. The generic fallback and the details panel are web-aware.
Fixture gains web_search and web_fetch turns for the built-boot snapshot.
