add GraphSim module

[LEXUGE]

Created a new GraphSim module.

• The code is properly formatted and commented.
• Substantial new functionality is documented within the docs.
• All new functionality is tested.
• All of the automated tests on github pass.
• We recently started enforcing formatting checks. If formatting issues are reported in the new code you have written, please correct them. There will be plenty of old code that is flagged as we are slowly transitioning to enforced formatting. Please do not worry about or address older formatting issues -- keep your PR just focused on your planned contribution.

[Copilot]

Pull Request Overview

This PR introduces a new GraphSim module to organize graph state simulation functionality. The change wraps existing graph simulation code in a dedicated module and updates import statements throughout the codebase to use the new module structure.

• Wraps existing graph state functionality in a new GraphSim module
• Updates all test files to import from QuantumClifford.GraphSim instead of QuantumClifford
• Imports specific functions from the new module into the main QuantumClifford namespace

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/graphs/graphs.jl	Creates the new GraphSim module wrapper with necessary imports
src/QuantumClifford.jl	Imports key GraphSim functions into main namespace
test/test_graphs_tables.jl	Updates imports to use GraphSim module
test/test_graphs_single_qubit_gates.jl	Updates imports to use GraphSim module
test/test_graphs_cphase.jl	Updates imports to use GraphSim module
test/test_graphs.jl	Updates imports to use GraphSim module

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[LEXUGE]

hmmmm @Krastanov I am not sure how to fix the doctest. Supposedly if it uses QuantumClifford then all the functions should be exported already.

[Krastanov]

Currently the doctests have not finished running, so I am not sure about them.

As for the documentation itself, the failure is in resolving the references. The rules for them are a bit different. Check the various module definitions in docs/make.jl and just add an extra one the way there are a few already for other submodules.

[LEXUGE]

@Krastanov I think it's now working:

• public API is exposed directly under QuantumClifford, not breaking existing API
• However, as benefits of the module, internal symbols won't be exposed / cause side-effects on other parts of the code.

[Krastanov]

@LEXUGE , could you remind me what the status here is? Is this ready for merge after a review or do we have any outstanding questions about it?

[LEXUGE]

It doesn't have anything outstanding pending on me. So should be OK to merge after a review

[LEXUGE]

@Krastanov Would you like to review this PR so I could push forward the graph state measurement and remaining cleanup/documentation.

Thanks!