build(deps-dev): bump vitepress from 1.6.3 to 1.6.4

Bumps [vitepress](https://github.com/vuejs/vitepress) from 1.6.3 to 1.6.4.
- [Release notes](https://github.com/vuejs/vitepress/releases)
- [Changelog](https://github.com/vuejs/vitepress/blob/v1.6.4/CHANGELOG.md)
- [Commits](vuejs/vitepress@v1.6.3...v1.6.4)

---
updated-dependencies:
- dependency-name: vitepress
  dependency-version: 1.6.4
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

bun.lock

@@ -11,7 +11,7 @@
   "devDependencies": {
     "@types/node": "^24.0.15",
     "prettier": "^3.6.2",
-    "vitepress": "^1.6.3",
+    "vitepress": "^1.6.4",
     "vitepress-export-pdf": "^1.0.0"
   },
   "dependencies": {