Ahnlich integration in VectorDBZ

[VectorDBZ](https://vectordbz.com/) has approved an Ahnlich DB integration.

Initial support will include:

- Connecting and listing stores
- Store information and predicate indexes
- Dense-vector search and metadata filtering
- Creating, dropping, and updating stores
- Upserting and deleting entries

This issue tracks implementation progress and any SDK or API limitations discovered along the way.

Related VectorDBZ issue: [link](https://github.com/vectordbz/vectordbz/issues/19)

Review the related VectorDBZ issue and the Ahnlich API or SDK entry points before mapping the listed operations: store management, indexes, search, filtering, upserts, and deletes. Done means the approved integration supports those operations and records any SDK or API limitations discovered.

Written by the indexing model from the issue text.