Move commented tests from resolveMdxUrl.ts to vitest (#516)

* Initial plan

* Add vitest infrastructure and move commented tests to vitest

Co-authored-by: abernier <76580+abernier@users.noreply.github.com>

* Address review feedback: remove @vitest/ui, merge test commands, simplify config

Co-authored-by: abernier <76580+abernier@users.noreply.github.com>

* .

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: abernier <76580+abernier@users.noreply.github.com>
Co-authored-by: Antoine BERNIER <antoine.bernier@gmail.com>

Author: Copilot

package.json

@@ -41,7 +41,8 @@
     "tailwindcss-animate": "^1.0.7",
     "tw-animate-css": "^1.4.0",
     "typescript": "^5.6.2",
-    "vite": "^7.3.1"
+    "vite": "^7.3.1",
+    "vitest": "^4.0.18"
   },
   "dependencies": {
     "@codesandbox/sandpack-react": "^2.20.0",
@@ -84,7 +85,7 @@
     "prepare": "husky && (test -f scripts/copy-fonts.sh && sh scripts/copy-fonts.sh || true)",
     "release": "changeset publish",
     "changeset": "changeset",
-    "test": "playwright test",
+    "test": "vitest && playwright test",
     "chromatic": "chromatic --project-token $CHROMATIC_PROJECT_TOKEN",
     "storybook": "storybook dev -p 6006",
     "build-storybook": "storybook build"