docs: Update dynamo_run.md with the information how to resolve ModuleNotFou… (#1691)

Author: tzulingk

docs/guides/dynamo_run.md

@@ -411,6 +411,22 @@ To pass extra arguments to the vllm engine see [Extra engine arguments](#extra-e
 
 vllm attempts to allocate enough KV cache for the full context length at startup. If that does not fit in your available memory pass `--context-length <value>`.
 
+If you see an error similar to the following:
+```text
+2025-06-28T00:32:32.507Z  WARN dynamo_run::subprocess: Traceback (most recent call last):
+2025-06-28T00:32:32.507Z  WARN dynamo_run::subprocess:   File "/tmp/.tmpYeq5qA", line 29, in <module>
+2025-06-28T00:32:32.507Z  WARN dynamo_run::subprocess:     from dynamo.llm import ModelType, WorkerMetricsPublisher, register_llm
+2025-06-28T00:32:32.507Z  WARN dynamo_run::subprocess: ModuleNotFoundError: No module named 'dynamo'
+```
+Then run
+```
+uv pip install maturin
+pip install patchelf
+cd lib/bindings/python
+maturin develop
+```
+this builds the Python->Rust bindings into that missing dynamo module. Rerun dynamo-run, the problem should be resolved.
+
 **Multi-GPU**
 
 Pass `--tensor-parallel-size <NUM-GPUS>` to `dynamo-run`.