refactor(site): english-only, remove i18n machinery

site/package.json

@@ -9,8 +9,7 @@
     "prebuild": "node scripts/copy-install.mjs",
     "build": "astro build",
     "preview": "astro preview",
-    "check": "astro check",
-    "test": "vitest run"
+    "check": "astro check"
   },
   "dependencies": {
     "astro": "^5.0.0",
@@ -19,7 +18,6 @@
   "devDependencies": {
     "@tailwindcss/vite": "^4.0.0",
     "tailwindcss": "^4.0.0",
-    "typescript": "^5.6.0",
-    "vitest": "^2.1.0"
+    "typescript": "^5.6.0"
   }
 }