Standardizes layer directory path resolution across obikindex, obikpartitionner, and obikphylo by replacing inline string formatting and join calls with the centralized obilayeredmap::layer_dir utility. This refactoring removes redundant path construction logic while preserving existing iteration bounds, control flow, and public APIs.
Restructure the project by moving the standalone compare_sparse utility into an example directory, removing Sankoff parameter configurations and benchmark scripts, updating version control ignores, and expanding the test suite with diagnostic checks and performance benchmarks.