swarm-ui: builds are a card under the job graph on the jobs tab

The builds tab is gone from the nav; its card sits below the jobs card on
/jobs. The swarm-builder commit status now links to /jobs?run=<id>, and the old
/builds address redirects there with its query so links already on PRs still
open the build. Docs and the link test follow.

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

@@ -58,7 +58,6 @@ const NAV_ITEMS: { href: string; label: string; accent: string }[] = [
   { href: "/notifications", label: "notifications", accent: "var(--yellow)" },
   { href: "/issues", label: "issues", accent: "var(--yellow)" },
   { href: "/review", label: "review", accent: "var(--amber)" },
-  { href: "/builds", label: "builds", accent: "var(--green)" },
   { href: "/components", label: "components", accent: "var(--blue)" },
 ];