Fix NVFP4 mapper: strip model. prefix from checkpoint keys

The NVFP4 checkpoint uses model.layers.* but vLLM's AutoWeightsLoader
expects layers.* (relative to the model module). Strip the model. prefix
instead of adding it.

vllm/patches/deepseek_v4.py

@@ -1667,9 +1667,8 @@ def _make_deepseek_v4_nvfp4_weights_mapper() -> WeightsMapper:
 
     return WeightsMapper(
         orig_to_new_prefix={
-            "layers.": "model.layers.",
-            "embed.": "model.embed.",
-            "norm.": "model.norm.",
+            # Strip model. prefix (checkpoint has it, model params don't)
+            "model.": "",
         },
         orig_to_new_regex=expert_rename_regex,
         orig_to_new_suffix=suffix_renames,