fix: resolve yarn.lock conflict by syncing Next.js version with react.dev

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: hg-pyun

package.json

@@ -38,7 +38,7 @@
     "classnames": "^2.2.6",
     "debounce": "^1.2.1",
     "github-slugger": "^1.3.0",
-    "next": "15.4.10",
+    "next": "15.1.11",
     "next-remote-watch": "^1.0.0",
     "parse-numeric-range": "^1.2.0",
     "react": "^19.0.0",