fix(deps): update dependency next to v16

Author: renovate[bot]

packages/docs/package.json

@@ -14,7 +14,7 @@
   "dependencies": {
     "@catppuccin/palette": "2.0.0-beta.1",
     "@docsearch/react": "^4.0.0",
-    "next": "^15.3.5",
+    "next": "^16.0.0",
     "nextra": "^4.4.0",
     "nextra-theme-docs": "^4.4.0",
     "react": "^19.1.0",