✨ Expose QDMI device queue depth

[burgholzer]

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Description

Expose the optional QDMI device queue depth through FoMaC as Device::getQueueDepth() -> std::optional<size_t> and Device.queue_depth() -> int | None. Unsupported devices remain valid and return an empty optional/None. The change also adds the diagnostic name, generated Python stub, and native/Python coverage.

This PR depends on QDMI #486 and pins its validated head 684aae5a959d63e3affb9428df2c4a0187bdb624 until the property is released. It does not change any bundled device implementation.

Validation

• release configure against QDMI PR 🐛 ZX PiExpression arithmetic not working properly #486
• cmake --build build/release --target mqt-core-fomac-test -j 4
• full native FoMaC suite (264/264 passed)
• uvx nox -s stubs
• uvx nox -s tests-3.13 -- test/python/fomac/test_fomac.py -k queue_depth (5/5 passed)
• uvx prek run --all-files

Checklist

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• I have added migration instructions to the upgrade guide (not needed).
• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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