Enable Astro TypeScript checks across preview, docs, and shared (#2743)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

docs/package.json

@@ -12,7 +12,7 @@
     "build": "pnpm run assets && astro build",
     "preview": "astro preview",
     "clean": "shx rm -rf dist public .astro",
-    "astro": "astro"
+    "type-check": "astro check"
   },
   "dependencies": {
     "@tabler/core": "workspace:*",
@@ -20,11 +20,13 @@
     "shiki": "^4.3.1"
   },
   "devDependencies": {
+    "@astrojs/check": "^0.9.4",
     "@astrojs/markdown-satteri": "^0.3.4",
     "@astrojs/mdx": "^7.0.3",
     "@tabler/preview": "workspace:*",
     "@types/node": "^26.1.1",
     "js-beautify": "^2.0.3",
-    "shx": "^0.4.0"
+    "shx": "^0.4.0",
+    "typescript": "^5.7.3"
   }
 }