chore(deps): update dependency vitepress to v1.6.4

Author: renovate[bot]

package.json

@@ -120,7 +120,7 @@
     "tsup": "8.5.0",
     "typescript": "5.8.3",
     "typescript-eslint": "8.37.0",
-    "vitepress": "1.6.3",
+    "vitepress": "1.6.4",
     "vitest": "3.2.4"
   },
   "peerDependencies": {