build(deps-dev): Bump @tailwindcss/postcss from 4.1.18 to 4.2.0

Bumps [@tailwindcss/postcss](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/@tailwindcss-postcss) from 4.1.18 to 4.2.0.
- [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/v4.2.0/packages/@tailwindcss-postcss)

---
updated-dependencies:
- dependency-name: "@tailwindcss/postcss"
  dependency-version: 4.2.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

package.json

@@ -31,7 +31,7 @@
     "@sveltejs/kit": "2.52.2",
     "@sveltejs/vite-plugin-svelte": "6.2.4",
     "@tailwindcss/forms": "0.5.11",
-    "@tailwindcss/postcss": "4.1.18",
+    "@tailwindcss/postcss": "4.2.0",
     "@testing-library/jest-dom": "6.9.1",
     "@types/gtag.js": "0.0.20",
     "@types/jsdom": "27.0.0",