Introduces a new `superkmer` command that implements a multi-stage pipeline for reading nucleotide pages and constructing superkmers with configurable parameters. The implementation uses partition-aware scatter writing via `obifastwrite` to distribute output batches across workers, and adds the necessary local dependencies to the project manifest.
This commit partitions the obikindex crate into multiple focused subcrates (obikfilter, obikmerge, obikquery, obikrebuild, obikselect, obikstats, obikdump, and obikidxcache) to reduce coupling and clarify module boundaries. It standardizes error handling across the workspace using OKIError and OKIResult, updates index APIs to support lazy, disk-backed partition access, and migrates NUMA system utilities to a new obisys crate. All modifications are structural, focusing on dependency graph expansion, import path updates, and API surface reorganization without altering core runtime behavior.