`adapter-static` configuration item `assets` does not affect `%sveltekit.assets%`

Describe the bug

When setting adapter-static configuration item assets to a custom location (e.g. the folder build/assets. The path %sveltekit.assets% and paths to other resources are not affected and they still point to /_app instead of assets/_app.

Reproduction

1. Open: https://stackblitz.com/edit/sveltejs-kit-template-default-yqrfta?file=build%2Findex.html
2. Run: npm i -D @sveltejs/adapter-static
3. Run: npm run build
4. Check out file paths at build/index.html

Logs

Logs are not relevant.

System Info

System info is not relevant.

Severity

annoyance

Additional Information

This is required in order to cleanly separate projects by namespacing URLs (e.g. /assets for Svelte and /api for REST). Then you can tell the web server to redirect /api to the backend and serve /assets to clients while still being able to serve index.html for domain /. There are many workarounds obviously, but no "clean" solutions (at least my opinion).

Start with the StackBlitz reproduction and inspect build/index.html after installing @sveltejs/adapter-static and running npm run build. Trace how the adapter-static assets option is applied to generated paths, and confirm done when %sveltekit.assets% and other resource paths use the configured assets location instead of /_app.