feat(adminsite): scaffold and site/'s token system

A fifth Next.js app, built like web/ and site/: App Router, React 18,
Tailwind 3, TanStack Query, standalone output.

app/globals.css carries site/app/globals.css's token blocks copied verbatim
rather than retyped, so the two cannot drift by transcription. Tailwind holds
var() references only -- no component or config entry may contain a hex
value. The semantic three are aliased: site/'s --up/--pend/--down become
valid/warn/expired, so each app names the colours for what it shows.

Unlike web/, there is no rewrite proxy: the browser calls admin directly, so
NEXT_PUBLIC_ADMIN_API_URL must be browser-reachable and listed in admin's
ADMIN_ORIGIN.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

adminsite/next.config.ts

@@ -0,0 +1,13 @@
+import type { NextConfig } from "next";
+
+/*
+ * Unlike web/, this app does NOT proxy /api through a rewrite. The browser
+ * calls admin directly, so NEXT_PUBLIC_ADMIN_API_URL must be reachable from the
+ * browser and must appear in admin's ADMIN_ORIGIN. lib/api.ts renders an
+ * explicit not-connected state when it is not.
+ */
+const nextConfig: NextConfig = {
+    output: "standalone",
+};
+
+export default nextConfig;