build: Add Dockerfile that uses NGC pytorch image

[chtruong814]

What does this PR do ?

Add Dockerfile that uses NGC pytorch image

• We need to build vllm from source to work with the pytorch in the container. This is installed with --no-deps to avoid overriding installed dependencies in the container such as torch and numpy.
• Move the uv install and cache directories to outside of root home directory to prevent them from being overridden if the root home directory is bind mounted when running the container
• Dependencies are installed into a single venv
• Ray workers use the system python executable rather than their own venv. This is controlled by setting the env var NEMO_RL_PY_EXECUTABLES_SYSTEM=1 in the container.
• uv sync is disabled to avoid unintentionally overriding installed dependencies
• Set VLLM_USE_STANDALONE_COMPILE=0 because vllm 0.10.0 sets that by default and it detects the torch version in the 25.06 pytorch container version as 2.8.0. However, the NGC container is missing some required methods to work correctly with that env var set.

Usage

• You can potentially add a usage example below

# Add a code snippet demonstrating how to use this

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Additional Information

• ...

[github-actions]

❌ Submodule Fast-Forward Check Failed

Check based on commit: 95126e2 (PR #897 from chtruong/build-ngc-torch)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/chtruong814/Megatron-LM/commits/2ff0f099ffc30ffd152e3e29e921a1609d00855c/
CURRENT (PR #897 from chtruong/build-ngc-torch): https://github.com/chtruong814/Megatron-LM/commits/ab433d69f50dd0fce828742431db1e5c7ac5a98d/

Please ensure all submodule commits are fast-forwards of the main branch before merging.

[github-actions]

❌ Submodule Fast-Forward Check Failed

Check based on commit: 95126e2 (PR #897 from chtruong/build-ngc-torch)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/chtruong814/Megatron-LM/commits/2ff0f099ffc30ffd152e3e29e921a1609d00855c/
CURRENT (PR #897 from chtruong/build-ngc-torch): https://github.com/chtruong814/Megatron-LM/commits/ab433d69f50dd0fce828742431db1e5c7ac5a98d/

Please ensure all submodule commits are fast-forwards of the main branch before merging.

[terrykong]

Is this comment in the description still accurate?

Mcore ref is updated to a newer version 0.13.0 but includes the RL specific changes. We'll want to bump to a newer Mcore commit later

[chtruong814]

@terrykong thanks for the review. could you take another look when you get a chance?