fix(container): add PYTHONPATH for sglang runtime to fix module discovery (#5071)

Signed-off-by: Dan Gil <dagil@nvidia.com>
Co-authored-by: Meenakshi Sharma <163925564+nvda-mesharma@users.noreply.github.com>

container/Dockerfile.sglang

@@ -518,6 +518,8 @@ ARG DYNAMO_COMMIT_SHA
 ENV DYNAMO_COMMIT_SHA=${DYNAMO_COMMIT_SHA}
 
 ENV PATH=/home/dynamo/.local/bin:$PATH
+# PYTHONPATH for root user access to dynamo packages (NVBug 5762058)
+ENV PYTHONPATH=/home/dynamo/.local/lib/python3.12/site-packages:$PYTHONPATH
 
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 ########## Development (run.sh, runs as root user) ########