44b0a92e67
Adds --mode wgan alongside flow/ddpm: both stages get a WGAN-GP generator/critic pair (giant.model.wgan) instead of flow matching, so inference is a single forward pass per stage rather than a 10-step ODE integration — the fast-eval architecture noted in the roadmap. predict/rollout auto-detect the mode from the checkpoint's model_config. Best-checkpoint selection for wgan uses marginal-KL against the EMA generators every epoch, since a critic loss isn't a monotone quality signal. --router is not supported together with --mode wgan. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>