docs: add documentation to storage-api public types Add doc comments to public structs, enums, and traits in storage-api crate to improve documentation coverage. Refs #741
* refactor: flatten test harness storage compat aliases * refactor: flatten rustfs storage compat aliases (#3597) * refactor: prune runtime storage compat surface (#3598) * refactor: flatten runtime secondary storage compat (#3599) * docs: add scheduler placement profiling baselines (#3600) * feat: add observability topology capability contracts (#3601)