Add PatchTST-FM support for levels

[spolisar]

Adds support for levels when using PatchTST-FM.

The quantile fix for #328 resolved the main issue that occurred when adding level support for PatchTST-FM, all that was left is removing a couple lines.

This should close #316.

TODO:

• merge in Support for Dask, PySpark, and Ray via Fugue #328 before this branch.

[Copilot]

Pull request overview

This PR enables level-based prediction intervals for the PatchTST-FM foundation model by removing the explicit guard that previously rejected level, and updates the model-level tests accordingly.

Changes:

• Remove ValueError that blocked level in PatchTST-FM’s forecast().
• Update test_using_level so PatchTST-FM is no longer treated as a “levels unsupported” model.
• Modify pyproject.toml optional dependency declarations (currently introduces a duplication issue).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
timecopilot/models/foundation/patchtst_fm.py	Removes the hard-coded rejection of level to allow interval outputs via QuantileConverter.
tests/models/test_models.py	Updates the “levels unsupported” model list to include PatchTST-FM in the positive path.
pyproject.toml	Adds a duplicated [project.optional-dependencies] table (needs correction).

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[AzulGarza]

thanks, lgtm!