refactor: 拆分 module.py 为 components 子包

- rope/linear/norm/embedding/mlp/attention/decoder_block 各自独立文件
- 依赖单向无循环
- 公开接口不变，外部无需修改

astrai/model/__init__.py

@@ -1,11 +1,9 @@
 from astrai.model.automodel import AutoModel
-from astrai.model.module import (
-    GQA,
-    MLP,
-    DecoderBlock,
-    Linear,
-    RMSNorm,
-)
+from astrai.model.components.attention import GQA
+from astrai.model.components.decoder_block import DecoderBlock
+from astrai.model.components.linear import Linear
+from astrai.model.components.mlp import MLP
+from astrai.model.components.norm import RMSNorm
 from astrai.model.transformer import Transformer
 
 __all__ = [