chore(deps): update UI deps; vitest 5 + jsdom 31 + plugin-react 6

next 16.4.6 / react 19.3.1 and other minors. Add missing StationConfig.id
to config test fixtures (newer next build type-checks tests/).
Tailwind v4 and TS 7 intentionally held.

mta-sign-ui/next-env.d.ts

@@ -1,6 +1,7 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
 import "./.next/types/routes.d.ts";
+import "./.next/types/root-params.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.