- add astrai/optim/composite.py with shared step/zero_grad/state_dict/param_groups helpers and OptimizerFactory
- rename MuonMix to MuonAdamW (matches registered name muon_adamw) and file to muon_adamw.py
- use @OptimizerFactory.register decorator in each optimizer module instead of post-import registration in __init__
- fix closure being invoked once per sub-optimizer in MuonAdamW.step (now exactly once via composite_step)
- NoraNAdamW.step now forwards closure correctly
ViperEkura
QueenAmish