Add secondary Nemotron perf/diagnostic patches (Liger, TP CE, FLOPs, benchmark)

[jasont314]

Adds auxiliary optimization and reporting updates separated from the core PP/EP/SQuAD correctness path.

What does this PR do ?

Introduces secondary Nemotron performance/diagnostic improvements (Liger integration path, TP CE handling, FLOPs accounting updates, and benchmark instrumentation) without changing the core PP/EP/SQuAD integration PR scope.

Changelog

• _transformers/kernel_patches.py
  • Add NemotronH-specific Liger patch path with optional RMSNorm and CE patch toggles.
• components/loss/masked_ce.py
  • Improve TP-aware masked CE behavior used in Nemotron runs.
• components/utils/flops_utils.py
  • Update FLOPs computation/reporting for better diagnostic fidelity.
• recipes/llm/benchmark.py
  • Add benchmark-side instrumentation/reporting improvements for run analysis.
• components/distributed/init_utils.py
  • Minor distributed init/reporting update used by benchmark diagnostics.
• NEMOTRON_SECONDARY_PATCH_NOTES.md
  • Add implementation notes and usage context for this secondary patch set.

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Additional Information

• Related to # (issue)
• Validation run:
  • python -m pytest -q tests/unit_tests/_transformers/test_auto_model.py tests/unit_tests/loss/test_masked_ce.py tests/unit_tests/utils/test_flops_utils.py tests/unit_tests/recipes/llm/test_benchmark.py
  • Result: 83 passed, 7 warnings

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