chore: upgrade astro to 6.0.4

- Bump @astrojs/check from 0.9.6 to 0.9.7
- Upgrade @astrojs/mdx from 4.3.13 to 5.0.0
- Update @astrojs/rss from 4.0.15 to 4.0.17
- Upgrade @astrojs/sitemap from 3.6.1 to 3.7.1
- Upgrade astro from 5.16.8 to 6.0.4

package.json

@@ -18,16 +18,16 @@
     "prepare": "husky"
   },
   "dependencies": {
-    "@astrojs/check": "^0.9.6",
-    "@astrojs/mdx": "^4.3.13",
-    "@astrojs/rss": "^4.0.15",
-    "@astrojs/sitemap": "^3.6.1",
+    "@astrojs/check": "^0.9.7",
+    "@astrojs/mdx": "^5.0.0",
+    "@astrojs/rss": "^4.0.17",
+    "@astrojs/sitemap": "^3.7.1",
     "@iconify-json/lucide": "^1.2.86",
     "@iconify-json/tabler": "^1.2.26",
     "@tailwindcss/vite": "^4.1.18",
     "@vercel/analytics": "^1.6.1",
     "@vercel/speed-insights": "^1.3.1",
-    "astro": "^5.16.8",
+    "astro": "^6.0.4",
     "astro-icon": "^1.1.5",
     "remark-reading-time": "^2.0.2",
     "tailwindcss": "^4.1.18",