[ENH] Add Moirai-MoE foundation model to v2 interface

[andersendsa]

Reference Issues/PRs

Fixes #2260

What does this implement/fix? Explain your changes.

This PR adds support for the Salesforce Moirai and Moirai-MoE foundation models into the v2 interface of pytorch-forecasting.

• Added Moirai and MoiraiMoE wrapper classes that inherit from TslibBaseModel in pytorch_forecasting/models/moirai/.
• Added corresponding package container classes Moirai_pkg_v2 and MoiraiMoE_pkg_v2 to conform to the v2 model registry.
• Exposed these new models and packages in pytorch_forecasting/models/init.py and pytorch_forecasting/models/moirai/init.py.
• Designed the integration to treat uni2ts as a soft dependency. Users can provide the underlying instantiated MoiraiMoEForecast or MoiraiForecast modules to the wrapper directly without hard-requiring uni2ts in the main package environment.

What should a reviewer concentrate their feedback on?

• Verification that the soft dependency pattern (passing the module directly) aligns well with the intended architecture for integrating external foundation models in the v2 interface.
• Review of the _tags dictionary within the *_pkg_v2 container definitions for Moirai and MoiraiMoE to ensure the metadata (like capabilities and computation tags) correctly reflects the expected model behavior.

Did you add any tests for the change?

The new models are automatically picked up by the existing PyTorch Forecasting v2 testing framework (specifically test_all_v2), which iterates over registered models ending in _pkg_v2. We have run the test_all_estimators_v2.py suite to ensure they instantiate correctly and do not break the class registry.

Any other comments?

PR checklist

• The PR title starts with either [ENH], [MNT], [DOC], or [BUG]. [BUG] - bugfix, [MNT] - CI, test framework, [ENH] - adding or improving code, [DOC] - writing or improving documentation or docstrings.
• Added/modified tests
• Used pre-commit hooks when committing to ensure that code is compliant with hooks. Install hooks with pre-commit install.
  To run hooks independent of commit, execute pre-commit run --all-files

[codecov]

Codecov Report

❌ Patch coverage is 53.70370% with 50 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@c4f5aac). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
...ytorch_forecasting/models/moirai/_moirai_moe_v2.py	37.83%	23 Missing ⚠️
pytorch_forecasting/models/moirai/_moirai_v2.py	37.83%	23 Missing ⚠️
...ch_forecasting/models/moirai/_moirai_moe_pkg_v2.py	85.71%	2 Missing ⚠️
...ytorch_forecasting/models/moirai/_moirai_pkg_v2.py	85.71%	2 Missing ⚠️

Additional details and impacted files

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Flag	Coverage Δ
cpu	86.77% <53.70%> (?)
pytest	86.77% <53.70%> (?)

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[andersendsa]

hi @phoeenniixx this pr passes all the test pls let me know if this pr needs any changes or if it is good to merge

[phoeenniixx]

Please atleast implement something

[phoeenniixx]

Thanks
But you have raised a PR that is just a bare bone implementation with no forward (throws NonImplementedError in this case)
Please donot blindly use AI and look what it is giving out before pushing

[andersendsa]

Thanks But you have raised a PR that is just a bare bone implementation with no forward (throws NonImplementedError in this case) Please donot blindly use AI and look what it is giving out before pushing

Hi sorry for the confusion the pr is still work in progress will make changes and revert