The binary quantizer uses D/8 for buffer sizes and memset, which
truncates for non-multiple-of-8 dimensions, causing OOB writes.
Rather than using ceiling division, enforce the constraint at
table creation time with a clear parse error.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Add inverted file (IVF) index type: partitions vectors into clusters via
k-means, quantizes to int8, and scans only the nearest nprobe partitions at
query time. Includes shadow table management, insert/delete, KNN integration,
compile flag (SQLITE_VEC_ENABLE_IVF), fuzz targets, and tests. Removes
superseded ivf-benchmarks/ directory.
