Bump vitest from 4.0.14 to 4.0.15 in /josh-ui

Bumps [vitest](https://github.com/vitest-dev/vitest/tree/HEAD/packages/vitest) from 4.0.14 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-patch
...

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

Author: dependabot[bot]

josh-ui/package-lock.json

@@ -54,6 +54,6 @@
     "jsdom": "^27.3.0",
     "serve": "^14.2.5",
     "vite": "^7.2.6",
-    "vitest": "^4.0.14"
+    "vitest": "^4.0.15"
   }
 }