chore(deps-dev): bump @tailwindcss/postcss in /templates/next-app

Bumps [@tailwindcss/postcss](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/@tailwindcss-postcss) from 4.1.18 to 4.2.2.
- [Release notes](https://github.com/tailwindlabs/tailwindcss/releases)
- [Changelog](https://github.com/tailwindlabs/tailwindcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/tailwindlabs/tailwindcss/commits/v4.2.2/packages/@tailwindcss-postcss)

---
updated-dependencies:
- dependency-name: "@tailwindcss/postcss"
  dependency-version: 4.2.2
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

templates/next-app/package.json

@@ -19,7 +19,7 @@
   },
   "devDependencies": {
     "@eslint/eslintrc": "^3",
-    "@tailwindcss/postcss": "^4.2.1",
+    "@tailwindcss/postcss": "^4.2.2",
     "@types/node": "^25.5.0",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",