DuckDB-HNSW-ACORN drops with pre-filtered vector search

DuckDB-HNSW-ACORN is a critical upgrade that transforms DuckDB into a top-tier vector database for metadata-heavy RAG applications. ACORN-1 pushes SQL WHERE clauses directly into the HNSW graph traversal, ensuring high recall even with highly restrictive filters that usually break standard ANN indexes. RaBitQ 1-bit quantization achieves massive memory efficiency, enabling millions of high-dimensional vectors to fit in RAM with minimal precision loss. Deep optimizer integration automatically rewrites complex metadata joins and grouped nearest-neighbor queries into optimized vector operations, effectively eliminating the need for external vector databases in local-first workflows while supporting standard distance metrics via DuckDB SQL syntax.