Env/fighter LoRA training for Z-Image misrouted to _train_sdxl (CLIPTokenizer
crash: "NoneType cannot be interpreted as an integer"). Cause: _resolve_base_model_path
returns the HF id verbatim (e.g. unsloth/Z-Image-Turbo-unsloth-bnb-4bit) when the
model has no local `path`, so the isdir(base_path/transformer) DiT check was False
and it fell through to the SDXL/SD15 trainer.

- Detect Z-Image by NAME (id contains z-image/zimage) in addition to the
  diffusers-config class name, so an HF-id base routes to _train_dit.
- _train_dit: when the base is a pre-quantized (bnb/nf4/4bit) build, train against
  the full Tongyi-MAI/Z-Image-Turbo instead (a 4-bit checkpoint isn't a clean
  full-precision LoRA base); the LoRA still applies to the quantized model at
  inference. Overridable via lora_train_base_model.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RdMufYvtTbtGDWsiZVoXce