vdjtools 5.0.0

Breaking API change: remove the formerly unused compare_models(labels=...) keyword, deprecated in 4.9.0. Remove it from table comparisons; use compare_net_dot(..., labels=("first", "second")) for graph labels. Distance-table columns and values are unchanged, and the CLI retains graph labels.

Gene-prior regression tests retain full TRB zero/default equivalence and share one positive-prior fit for invariants. Exact M-step edge cases now run on every CI platform. On a 16-core Mac with the same native Release build, the original four tests took 122.81 seconds and the optimized suite plus five new cases took 89.21 seconds. Native E-step calls fell from 11 to 7; production inference and fitted artifacts are unchanged.