Bump tailwindcss from 3.4.9 to 4.2.4 in /web

Bumps [tailwindcss](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/tailwindcss) from 3.4.9 to 4.2.4.
- [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/v4.2.4/packages/tailwindcss)

---
updated-dependencies:
- dependency-name: tailwindcss
  dependency-version: 4.2.4
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

web/package.json

@@ -134,7 +134,7 @@
     "postcss": "^8.5.8",
     "prettier": "^3.3.3",
     "prettier-plugin-tailwindcss": "^0.6.5",
-    "tailwindcss": "^3.4.9",
+    "tailwindcss": "^4.2.4",
     "typescript": "^5.9.3",
     "vite": "^6.4.2",
     "vitest": "^3.0.7"