fix: fsdp=True instead of list + add activation_checkpointing

train.py

@@ -167,13 +167,14 @@ def train(config_path):
         eval_steps=config.get("eval_steps", 100),
         bf16=True,
         gradient_checkpointing=config.get("gradient_checkpointing", True),
-        fsdp=["full_shard", "auto_wrap"],
+        fsdp=True,
         fsdp_config={
             "backward_prefetch": "backward_pre",
             "forward_prefetch": "true",
             "cpu_offload": "false",
             "auto_wrap_policy": "TRANSFORMER_BASED_WRAP",
             "transformer_layer_cls_to_wrap": "Qwen3_5MoeDecoderLayer",
+            "activation_checkpointing": True,
         },
     )