- Replace hand-rolled BaseConfig (from_dict/to_dict/_coerce/_unwrap_optional) with pydantic.dataclasses
- from_dict now uses cls(**d), to_dict uses dataclasses.asdict + json.dumps filter
- TrainConfig: required fields are now truly required (no default=None), delete manual validate()/__post_init__
- Remove dead required() helper and metadata={'help': ...} annotations
- Fix gradient_checkpointing_modules type from List[str] to List[type]
- Add pydantic>=2.0 as direct dependency in pyproject.toml
- Add numpy-style Parameters docstrings to all config classes
- Enable use_attribute_docstrings in BaseConfig for schema generation
- LoRAConfig also migrated to pydantic dataclass
When `inject_lora()` replaces Linear layers with LoRALinear after the model
has been moved to CUDA, the new lora_A and lora_B parameters were always
created on CPU, causing a device mismatch error during the forward pass.
Now lora_A and lora_B are created on the same device and dtype as the
parent weight, matching the model's current device.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>