Asset placement

Result: native. Docusaurus supports two useful models:

• docs/criteria/demo-asset.svg is referenced relatively and handled by the module bundler.
• static/img/docusaurus-demo.svg is copied byte-for-byte to the locale build.

Co-located files move with their document and can be fingerprinted. Static files keep predictable names, which is useful for downloads and external references but puts cache invalidation and optimization on the author.