Update dependency postcss to v8.5.23 [SECURITY] (#312)

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

Author: renovate[bot]

package-lock.json

@@ -130,7 +130,7 @@
     "ollama-ai-provider": "1.2.0",
     "openai": "5.23.2",
     "pkg-pr-new": "0.0.66",
-    "postcss": "8.5.18",
+    "postcss": "8.5.23",
     "prettier": "3.8.1",
     "react": "19.2.4",
     "react-dom": "19.2.4",