Bump postcss from 8.5.15 to 8.5.16

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.15 to 8.5.16.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.15...8.5.16)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.16
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -18,7 +18,7 @@
     "@types/react": "19.2.17",
     "@types/react-dom": "^19.2.3",
     "next": "^16.2.9",
-    "postcss": "^8.5.15",
+    "postcss": "^8.5.16",
     "react": "^19.2.7",
     "react-dom": "^19.2.7",
     "react-use-websocket": "^4.13.0",