Bump tailwindcss from 3.4.19 to 4.3.0 in /frontend

Bumps [tailwindcss](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/tailwindcss) from 3.4.19 to 4.3.0.
- [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/v4.3.0/packages/tailwindcss)

---
updated-dependencies:
- dependency-name: tailwindcss
  dependency-version: 4.3.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

frontend/package.json

@@ -29,7 +29,7 @@
     "eslint-config-next": "^16.2.6",
     "postcss": "^8.5.4",
     "prettier": "^3.5.3",
-    "tailwindcss": "^3.4.17",
+    "tailwindcss": "^4.3.0",
     "typescript": "^5.8.3"
   }
 }