Manticore Search 27.1.5: Auth, sharding, conversational and faster vector search

Manticore Search 27.1.5 introduces built-in authentication and authorization, sharded tables for easier write-heavy deployments, and conversational search capabilities that enable document Q&A directly over vectorized data. The release also includes significant performance improvements for vector search through multithreaded HNSW builds, faster KNN operations, and enhancements to faceting and aggregations across numerous bug fixes.