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/package.json

@@ -0,0 +1,37 @@
+{
+    "name": "vantage-adminsite",
+    "version": "0.1.0",
+    "private": true,
+    "scripts": {
+        "dev": "next dev",
+        "build": "next build",
+        "start": "next start",
+        "lint": "next lint",
+        "test": "vitest run",
+        "test:watch": "vitest"
+    },
+    "dependencies": {
+        "next": "16.2.9",
+        "react": "^18.3.1",
+        "react-dom": "^18.3.1",
+        "@tanstack/react-query": "^5.51.1",
+        "clsx": "^2.1.1"
+    },
+    "devDependencies": {
+        "@types/node": "^20.14.11",
+        "@types/react": "^18.3.3",
+        "@types/react-dom": "^18.3.0",
+        "@testing-library/react": "^16.0.0",
+        "@testing-library/user-event": "^14.5.2",
+        "@testing-library/jest-dom": "^6.4.8",
+        "@vitejs/plugin-react": "^4.3.1",
+        "autoprefixer": "^10.4.19",
+        "eslint": "^9.0.0",
+        "eslint-config-next": "16.2.9",
+        "jsdom": "^24.1.1",
+        "postcss": "^8.4.39",
+        "tailwindcss": "^3.4.6",
+        "typescript": "^5.5.3",
+        "vitest": "^2.0.5"
+    }
+}