We do, from years ago, with embedding stored as blobs (well before sqlite_vss). No SQLite extension but some user-defined functions for some distance operations and for others we are able to load all weights into memory and perform the ops there (data is small enough).

Another comment mentioned meilisearch. You might be interested in the fact that a recent rearchitecture of their codebase split it into a library that can be embedded into your app without needing a separate process.