chore: update dependencies and configuration for Vite and Vitest

- Bump versions of @vitejs/plugin-react, @vitest/coverage-istanbul, @vitest/coverage-v8, and @vitest/ui to their beta releases.
- Upgrade Vite and Vitest to their respective beta versions.
- Adjust Vite configuration to disable code splitting for improved React initialization stability.

package.json

@@ -25,6 +25,6 @@
     "prettier-plugin-tailwindcss": "^0.7.2",
     "tar": "^7.5.11",
     "typescript": "^6.0.1-rc",
-    "vite": "^7.3.1"
+    "vite": "^8.0.0-beta.18"
   }
 }