chore: Added Vitest GitHub workflow

Author: Venefilyn

frontend/package.json

@@ -25,6 +25,7 @@
     "@types/react": "^18.3.10",
     "@types/react-dom": "^18.3.0",
     "@vitejs/plugin-react": "^4.3.2",
+    "@vitest/coverage-v8": "^2.1.5",
     "happy-dom": "^15.7.4",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",