chore: Switch to mcore upstream main

[ahmadki]

What does this PR do ?

The PR replaces the mcore fork created for RL with upstream version

Issues

List issues that this PR closes (syntax):

Usage

• You can potentially add a usage example below

# Add a code snippet demonstrating how to use this

Before your PR is "Ready for review"

Pre checks:

• Make sure you read and followed Contributor guidelines
• Did you write any new necessary tests?
• Did you run the unit tests and functional tests locally? Visit our Testing Guide for how to run tests
• Did you add or update any necessary documentation? Visit our Document Development Guide for how to write, build and test the docs.

Additional Information

• ...

[github-actions]

❌ Submodule Fast-Forward Check Failed

Check based on commit: e5d1ae9 (PR #1990 from ahmadki/mcore_main)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/NVIDIA/Megatron-LM/commits/193463c4f8414e6906a40dd527a450bca50706b1/
CURRENT (PR #1990 from ahmadki/mcore_main): https://github.com/NVIDIA/Megatron-LM/commits/0d0943c6bfa9cbb30fcd62d40ce1792c4cb201e8/

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: c19ee75 (PR #1990 from ahmadki/mcore_main)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/NVIDIA/Megatron-LM/commits/b12071b947f9ee3c6616306662069fc4ca77be4c/
CURRENT (PR #1990 from ahmadki/mcore_main): https://github.com/NVIDIA/Megatron-LM/commits/0d0943c6bfa9cbb30fcd62d40ce1792c4cb201e8/

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: 891b3c2 (PR #1990 from ahmadki/mcore_main)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/NVIDIA/Megatron-LM/commits/b12071b947f9ee3c6616306662069fc4ca77be4c/
CURRENT (PR #1990 from ahmadki/mcore_main): https://github.com/NVIDIA/Megatron-LM/commits/0d0943c6bfa9cbb30fcd62d40ce1792c4cb201e8/

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: 6674072 (PR #1990 from ahmadki/mcore_main)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/NVIDIA/Megatron-LM/commits/b12071b947f9ee3c6616306662069fc4ca77be4c/
CURRENT (PR #1990 from ahmadki/mcore_main): https://github.com/NVIDIA/Megatron-LM/commits/0d0943c6bfa9cbb30fcd62d40ce1792c4cb201e8/

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: 924e32a (PR #1990 from ahmadki/mcore_main)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/NVIDIA/Megatron-LM/commits/b12071b947f9ee3c6616306662069fc4ca77be4c/
CURRENT (PR #1990 from ahmadki/mcore_main): https://github.com/NVIDIA/Megatron-LM/commits/0d0943c6bfa9cbb30fcd62d40ce1792c4cb201e8/

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: 4ba7f09 (PR #1990 from ahmadki/mcore_main)

✅ Submodules that are properly updated:

Megatron-Bridge: ✅ PR branch is ahead of main branch (fast-forward)

❌ Submodules that need attention:

Megatron-LM: ❌ Commits have DIVERGED from a common ancestor
TARGET (main branch): https://github.com/NVIDIA/Megatron-LM/commits/b12071b947f9ee3c6616306662069fc4ca77be4c/
CURRENT (PR #1990 from ahmadki/mcore_main): https://github.com/NVIDIA/Megatron-LM/commits/0d0943c6bfa9cbb30fcd62d40ce1792c4cb201e8/

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