fix: close release preflight gaps

Route public health checks to the API, backfill and synchronize job opportunities, stabilize SPA smoke tests, and document operator-only production steps.

job-tracker-ui/app/[[...slug]]/page.tsx

@@ -1,15 +0,0 @@
-import ClientShell from "./ClientShell";
-
-// Optional catch-all so EVERY path (/, /cv/{slug}, /career/builder/…) resolves to this same shell on
-// a hard load. Without it, `output: export` only generates `/`, and Next's client renders its
-// not-found for any deep URL before React Router can route it — breaking refresh and shared links.
-// generateStaticParams emits just index.html (the empty slug); nginx (try_files $uri /index.html)
-// serves that shell for every unknown path, and this catch-all matches it client-side so React
-// Router takes over. See docs/architecture/frontend.md (SPA routing).
-export function generateStaticParams() {
-  return [{ slug: [] }];
-}
-
-export default function Page() {
-  return <ClientShell />;
-}