Refactors obikindex and obikpartitionner to delegate index construction to a new layered MPHF implementation. Adds resume-safe building with abundance filtering and count persistence, while introducing a PartitionMeta struct for JSON configuration persistence. Updates OKIError to wrap layer-specific errors, replaces single-path extraction with full path collection and logging, and registers new internal dependencies across the workspace.
Extracted core indexing logic, state tracking, and metadata management into a new `obikindex` crate. Refactored the `index` and `unitig` commands to leverage the `KmerIndex` abstraction and state-driven pipeline transitions. Removed obsolete CLI subcommands (`count`, `fasta`, `longtig`, `partition`) and their associated pipeline steps. Updated FASTA writing utilities for single-line output and deterministic identifiers, and refreshed workspace dependencies.