build(deps): make mlflow and wandb optional extras

[piyushumate]

What does this PR do?

Make mlflow and wandb optional extras instead of hard core dependencies. Closes #3783.

Changelog

• pyproject.toml: remove mlflow and wandb>=0.28.0 from dependencies[]; add [mlflow] (→ mlflow-skinny), [mlflow-full] (→ full mlflow), [wandb], and [tracking] (meta-extra) in [project.optional-dependencies]; wire [tracking] into [all]; fix all composite extras to use canonical distribution name nemo-automodel (hyphens)
• nemo_automodel/shared/import_utils.py (existing): safe_import / safe_import_from now used for all optional-dep guards per CLAUDE.md coding style rule
• components/loggers/loggers.py: module-level safe_import for wandb / mlflow; remove inline try/except ImportError from WandbConfig.build() and MLflowConfig.build()
• components/loggers/wandb_utils.py: remove inline try/except in init_wandb_run; defer error to safe_import placeholder at call time; uv-based install hint
• 8 recipe files (llm/train_ft, llm/kd, llm/train_seq_cls, dllm/train_ft, diffusion/train, vlm/finetune, vlm/kd, multimodal/finetune): replace top-level import wandb / import mlflow with module-level safe_import calls (returns boolean flag + module-or-placeholder); prefix every wandb.run is not None guard with _HAS_WANDB and and every mlflow.active_run() is not None with _HAS_MLFLOW and to short-circuit safely without installing the extras
• tests/unit_tests/loggers/test_optional_logger_extras.py [NEW]: unit tests covering instantiation without extras, UnavailableError on build() with absent extras, pyproject.toml extras schema, and recipe module _HAS_* sentinel presence
• ruff format + ruff check --fix applied to all changed files

Install patterns

uv add nemo-automodel                   # lean — no logger overhead
uv add nemo-automodel[mlflow]           # MLflow skinny (no mlflow vs mlflow-skinny conflict)
uv add nemo-automodel[mlflow-full]      # full MLflow stack (UI, SQL, pyarrow)
uv add nemo-automodel[wandb]            # W&B only
uv add nemo-automodel[tracking]         # both backends
uv add nemo-automodel[all]              # everything (includes tracking)

Before your PR is "Ready for review"

Pre checks:

• Make sure you read and followed Contributor guidelines
• Did you write any new necessary tests? — yes: tests/unit_tests/loggers/test_optional_logger_extras.py
• Did you add or update any necessary documentation?

Additional Information

• Related to [packaging] Make mlflow and wandb optional extras (not hard deps); switch to mlflow-skinny by default #3783
• Precedent: sagemaker-mlflow PR #22 applied the identical mlflow → mlflow-skinny + [full] pattern

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[piyushumate]

Hi @akoumpa @HuiyingLi — could you approve the CI workflows for this community PR when you get a chance?

This removes mlflow and wandb from hard core dependencies and moves them to optional extras ([mlflow], [mlflow-full], [wandb], [tracking]), fixing the mlflow vs mlflow-skinny mutual-exclusion conflict that breaks installs in SageMaker environments.

Closes #3783. Happy to address any review feedback. Thanks!

[akoumpa]

/ok to test d10f565

[piyushumate]

@akoumpa Updated both lockfiles (uv.lock), resolved ty type checking rules, and verified that all linters, formatting, and unit tests pass locally. Just curious, Is there a way i can trigger or CI has to go through maintainers?

[akoumpa]

/ok to test a2f9e11

[piyushumate]

@akoumpa is the CI expected to take this much time? It seems to be stuck in queue. Do lemme know if I am missing anything

[akoumpa]

Hi @piyushumate apologies for the delay; the CI workers are oversubscribed, thus the delay :( I'll mention this to our automation folks to explore any potential solution -- in the meantime, i'll open a separate PR to run CI to leverage separate CI worker queue, if that passes, i'll FM your PR.

[piyushumate]

Hi @akoumpa — updated commit 8ae1f40 to disable W&B interactive prompts (resolving the CI CPU/GPU timeouts) and use mlflow-skinny compatible file storage in unit tests

[piyushumate]

@akoumpa CI passed, please lemme know if anything else is needed. Thanks!

[akoumpa]

Hi @piyushumate can you take a look at the conflicts? i can rerun ci then

[piyushumate]

@akoumpa, conflicts have been resolved and the branch is rebased onto latest main. Both lockfiles have been regenerated and verified locally, and all linters and tests pass. Ready for CI. Thanks!

[akoumpa]

/ok to test 080ad40

[piyushumate]

@akoumpa seems like CI oversubscribed? (nvm , it passed)