chore: update vitest 1→4, add vite 8

vitest 4 requires vite ^6, so vite is added as an explicit devDependency.
Fixes esbuild vulnerability in vitest>vite path (GHSA-67mh-4wv8-2f99).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: yamatatsu

package.json

@@ -55,7 +55,8 @@
     "prettier": "^3.2.5",
     "typescript": "^5.4.3",
     "unbuild": "^2.0.0",
-    "vitest": "^1.4.0"
+    "vite": "^8.0.3",
+    "vitest": "^4.1.2"
   },
   "peerDependencies": {
     "@aws-sdk/client-athena": "^3.x.x"