fix(deps): update dependency astro to v6

Author: renovate[bot]

package.json

@@ -18,7 +18,7 @@
 	"dependencies": {
 		"@astrojs/sitemap": "^3.5.0",
 		"@iconify-json/heroicons": "^1.2.2",
-		"astro": "^5.13.2",
+		"astro": "^6.0.0",
 		"astro-icon": "^1.1.5",
 		"leaflet": "^2.0.0-alpha",
 		"tailwindcss": "^4.1.11"