added muon optimizer component

[BlueCrescent]

What does this PR do?

This PR adds muon optimizer component

General Changes

• Adde component
• Added some tests for optimizer factory

Checklist before submitting final PR

• My PR is minimal and addresses one issue in isolation
• I have merged the latest version of the target branch into this feature branch
• I have reviewed my own code w.r.t. correct implementation, missing type hints, proper documentation, etc.
• I have run a sample config for model training
• I have checked that all tests run through (python tests/tests.py)
• I have updated the internal changelog (CHANGELOG_DEV.md)

[Copilot]

Pull request overview

This PR adds support for a new Muon optimizer component to the Modalities component/registry system, including configuration wiring and unit tests to ensure the optimizer factory constructs the optimizer using the expected parameter groups.

Changes:

• Added OptimizerFactory.get_muon(...) that builds a Muon optimizer from get_optimizer_groups(...).
• Introduced MuonOptimizerConfig and registered the "optimizer" / "muon" component variant.
• Added unit tests verifying optimizer factory methods construct Adam/AdamW/Muon using computed optimizer groups.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
tests/test_optimizer_factory.py	Adds unit tests for Adam/AdamW/Muon factory construction and checkpointed optimizer loading behavior.
src/modalities/registry/components.py	Registers the new "muon" optimizer component variant and wires it to MuonOptimizerConfig.
src/modalities/optimizers/optimizer_factory.py	Adds get_muon factory method and imports Muon from torch.optim.
src/modalities/config/config.py	Adds MuonOptimizerConfig to represent Muon optimizer configuration in the component system.

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[le1nux]

Two tiny comments. I'll leave the final decision to you. Apart from that all looks good to me and can be merged :)

[le1nux]

Should we upgrade this to FSDP2 since FSDP1 is anyways deprecated?

[le1nux]

not sure if these optimizer_builds_optimizer_from_groups tests are important. To me they don't really test anything apart from making sure that the factory calls the right opimizer functions.