deps(deps-dev): bump vitest from 3.2.4 to 4.0.15

Bumps [vitest](https://github.com/vitest-dev/vitest/tree/HEAD/packages/vitest) from 3.2.4 to 4.0.15.
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v4.0.15/packages/vitest)

---
updated-dependencies:
- dependency-name: vitest
  dependency-version: 4.0.15
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

package.json

@@ -9,7 +9,7 @@
     "eslint": "^9.39.1",
     "prettier": "^3.7.4",
     "typescript": "^5.9.3",
-    "vitest": "^3.1.4",
+    "vitest": "^4.0.15",
     "wrangler": "^4.47.0"
   },
   "name": "xget",