chore(deps): update vitest monorepo to v4.0.18

Author: renovate[bot]

package.json

@@ -40,7 +40,7 @@
     "@codemirror/view": "^6.39.2",
     "@testing-library/dom": "^10.4.1",
     "@vitest/browser-playwright": "^4.0.15",
-    "@vitest/coverage-v8": "4.0.17",
+    "@vitest/coverage-v8": "4.0.18",
     "codemirror": "^6.0.2",
     "jsdom": "^27.3.0",
     "playwright": "^1.57.0",