Update dependency next to v15.5.7 [SECURITY] (#248)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -28,7 +28,7 @@
     "ky": "^1.8.1",
     "matter-js": "^0.20.0",
     "motion": "^12.23.3",
-    "next": "15.5.6",
+    "next": "15.5.7",
     "overlay-kit": "^1.8.4",
     "pretendard": "^1.3.9",
     "react": "^19.0.0",