swarm-ui: a review try-out page

A page to try a review classification against a real PR: repo, PR number and one or more classifications (name, description, polarity, threshold). Run posts to the controller's try-out endpoint and polls until the run is done or failed, saying it is running meanwhile, then shows the review's table, the overall verdict and the head commit. A row that could not run shows its error in place of a reason, and a failed run shows its error. The inputs stay so the run can be edited and repeated. Nothing is stored and nothing is posted to the forge. Route, nav entry and a section in docs/swarm/ui.md.

frontend/packages/swarm-ui/src/shell/Shell.tsx

@@ -51,6 +51,7 @@ const NAV_ITEMS: { href: string; label: string; accent: string }[] = [
   { href: "/jobs", label: "jobs", accent: "var(--pink)" },
   { href: "/schedules", label: "schedules", accent: "var(--cyan)" },
   { href: "/issues", label: "issues", accent: "var(--yellow)" },
+  { href: "/review-tryout", label: "review try-out", accent: "var(--red)" },
   { href: "/components", label: "components", accent: "var(--blue)" },
 ];
 
@@ -61,7 +62,7 @@ const NAV_ITEMS: { href: string; label: string; accent: string }[] = [
 // modifier alongside the base class, not a replacement, so every other
 // route's layout is untouched. `/agents` joined for the same reason —
 // its own table view (plus the list+detail split) hits the same cap.
-const WIDE_BODY_ROUTES = new Set(["/issues", "/agents"]);
+const WIDE_BODY_ROUTES = new Set(["/issues", "/agents", "/review-tryout"]);
 
 // `/agents/:name/terminal` (and a subagent's, under
 // `/agents/:name/subagents/:subagent/`) is full-bleed: the terminal fills