- rate_tree.rs: logarithmic neighbor selection in stochastic simulations (huge speedup).
- explore.rs: basic neighborhood (macrostate) exploration (ff-locmin).
- rate_model.rs: Kawasaki rate model.
- multi_pair_table.rs: new structures for MultiPairTable & StrandPairTable
- Major rewriting of LoopStructure and LoopStructureSSA
- Using FxHashMap instead of AHashMap for performance.
- multifold evaluation (changes across many files)
- Cargo bench updates.
- Macrostate naming.

- Removed preliminary implementations for commit & delay.
- Removed preliminary implementations for coaxial stacking.

- ff-eval now supports multi-fold
- ff-locmin release
- Kawasaki support for ff-trajectory / ff-timecourse
- ff-trajectory output formating
- ff-timecourse k0 default for consistency