ci: AUT-1141 skip MBridge dispatch for docs-only changes

[svcnemo-autobot]

Background

Docs-only Megatron-LM changes should not launch downstream Megatron-Bridge testing.

What changed

Gate the MBridge downstream job on pre-flight docs_only == 'false'.

Details

flowchart LR
    P[Pre-flight] --> D{Docs only?}
    D -->|Yes| S[Skip MBridge]
    D -->|No| M[Evaluate MBridge trigger]

Loading

The existing label, merge-group, and nightly trigger behavior remains unchanged for non-docs changes. This is paired with the companion Megatron-Bridge classification fix.

Tested

• bash tools/autoformat.sh with CI lint environment: passed
• Parsed .github/workflows/cicd-main.yml with PyYAML
• git diff --check

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[svcnemo-autobot]

/ok to test 77ac689

[svcnvidia-nemo-ci]

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You can track the progress here: https://github.com/NVIDIA/Megatron-LM/actions/runs/30478211524

[svcnvidia-nemo-ci]

🔄 Merge queue validation started!

You can track the progress here: https://github.com/NVIDIA/Megatron-LM/actions/runs/30479289586

[svcnvidia-nemo-ci]

🔄 Merge queue validation started!

You can track the progress here: https://github.com/NVIDIA/Megatron-LM/actions/runs/30483922484

[svcnvidia-nemo-ci]

🔄 Merge queue validation started!

You can track the progress here: https://github.com/NVIDIA/Megatron-LM/actions/runs/30483981211

[svcnvidia-nemo-ci]

🔄 Merge queue validation started!

You can track the progress here: https://github.com/NVIDIA/Megatron-LM/actions/runs/30484677976