Add comprehensive documentation for the `obilayeredmap` crate, `PersistentCompactIntVec`, `PersistentBitVec`, and the hierarchical k-mer index architecture, including sidebar navigation updates across all documentation pages. Refactor the Bray-Curtis distance computation in `obicompactvec` to decouple numerator and denominator calculations, replacing direct pairwise calls with explicit loops over precomputed sums. Update tests to verify column sum accuracy and align with the simplified API.
Introduces `partial_jaccard_dist` to return raw intersection and union counts, improving Jaccard distance flexibility. Corrects `not()` to explicitly zero padding bits in the final word, ensuring accurate bit-counting for partially-filled words. Adds an optimized `build_from_counts` constructor.