fix(deps): update dependency next to v15

Author: renovate[bot]

package.json

@@ -13,7 +13,7 @@
     "@radix-ui/colors": "^3.0.0",
     "@stitches/react": "^1.2.6",
     "date-fns": "^4.0.0",
-    "next": "14.2.21",
+    "next": "15.2.0",
     "react": "19.0.0",
     "react-dom": "19.0.0"
   },