refactor: keep muon_adamw as default optimizer and drop nora docs

- revert CLI/create_optimizer/display defaults to muon_adamw
- revert README, README-zh-CN, params.md to pre-merge state

README.md

@@ -101,9 +101,7 @@ nohup python scripts/tools/train.py \
     --batch_per_device=4 \
     --grad_accum_steps=8 \
     --warmup_ratio=0.05 \
-    --optimizer=nora_nadamw \
     --max_lr=1e-4 \
-    --nora_lr=5e-3 \
     --max_grad_norm=1.0 \
     --weight_decay=0.1 \
     --window_size=2048 \
@@ -258,4 +256,4 @@ This project is licensed under the [GPL-3.0 License](LICENSE).
 
 <div align="center">
   <em>A lightweight Transformer framework designed for both high performance and ease of use.</em>
-</div>
+</div>