Bump tailwindcss from 4.1.18 to 4.2.1 (#639)

Bumps [tailwindcss](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/tailwindcss) from 4.1.18 to 4.2.1.
- [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/v4.2.1/packages/tailwindcss)

---
updated-dependencies:
- dependency-name: tailwindcss
  dependency-version: 4.2.1
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -29,7 +29,7 @@
     "marked": "^17.0.1",
     "nodemon": "^3.1.11",
     "pdfobject": "^2.3.1",
-    "tailwindcss": "^4.1.18",
+    "tailwindcss": "^4.2.1",
     "vite": "^7.3.1"
   }
 }