Show HN: DuckDB community extension for prefiltered HNSW using ACORN-1

Hey folks! As someone doing hybrid search daily and wishing I could have a pgvector-like experience but with actual prefiltered approximate nearest neighbours, I decided to just take a punt on implementing ACORN on a fork of the DuckDB VSS extension. I had to make some changes to (vendored) usearch that I'm thinking of submitting upstream. But this does the business. Approximate nearest neighbours with WHERE prefiltering.

Edit: Just to clarify, this has been accepted into the community extensions repo. So you can use it like:

```

INSTALL hnsw_acorn FROM community;

LOAD hnsw_acorn;

```