1.4.7

What's new

• freeze() / unfreeze() — drop and restore the per-shard {i}.codes.npy / {i}.residuals.npy files for read-only indexes, roughly halving on-disk size. Search is unaffected; update() / delete() raise on a frozen index until unfreeze() is called. The unfreeze rebuild is byte-identical to the original Rust-written shards.

See PR #45 for details.