d9aa211b8fc79a71a9cdbab3b939df312725ed8a
This commit introduces a new `rebuild` CLI subcommand that reconstructs an existing multi-layer k-mer index into a compact, single-layer index. It implements a configurable filtering pipeline supporting min/max genome fraction/count and total count thresholds, parallel partition processing via `rayon`, and CLI progress tracking. The change also restructures module declarations across `obikindex` and `obikpartitionner` to integrate the new rebuild and layer-handling logic.