Introduce the `index` CLI subcommand, implementing a resumable, multi-stage pipeline to partition, dereplicate, and count kmers from input sequences. The command builds a layered de Bruijn graph index per partition, applies optional abundance filtering, and persists unitigs alongside an MPHF-based count matrix. Update `Cargo.toml` and `Cargo.lock` to include new dependencies (`epserde`, `ptr_hash`, `cacheline-ef`, `obicompactvec`, `obilayeredmap`) required for the index builder, and refresh the profiling data files.
Introduces the `obilayeredmap` crate (v0.1.0), implementing an append-only, disk-backed k-mer index using a minimal perfect hash function (MPHF). The module features memory-mapped reads, buffered writes, custom error handling, partition metadata persistence, and comprehensive unit tests. Also adds a reverse complement benchmark for `obikseq` and updates `Cargo.lock` with the new dependencies.
Eric Coissac