fix(device): require canonical Python device names

[tqchen]

Summary

• remove the Python-only llvm, c, test, nvptx, and cl device aliases
• retain canonical device names and their existing error behavior
• cover direct construction and typed FFI conversion rejection

Testing

• pytest -o addopts= tests/python/test_device.py tests/python/test_function.py tests/python/test_type_converter.py
• scoped pre-commit hooks, including Ruff, Cython lint, and ty

[gemini-code-assist]

Code Review

This pull request removes non-canonical device aliases (such as "llvm", "c", "test", "nvptx", and "cl") from the Cython device mapping and adds corresponding tests to ensure they are rejected. The reviewer noted an inconsistency where the C++ FFI parser accepts "mps" and "wgpu" but the Python constructor does not, and suggested adding "mps" to the mapping to maintain consistency.

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