WIP: Automated Equivalence Checking

[MaxieHelenBichmann]

Description

Equivalence-checking methods for deciding permutation and local Clifford equivalence of stabilizer and CSS codes; developed for my bachelor's thesis.

Some cleanups need to be done, and bigger picture questions answered, otherwise finished.

• potentially reduce from whole submodule to utility functions, or methods of *Code ?
• where to put documentation?

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.
• 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

❌ Patch coverage is 94.56869% with 34 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...mqt/qecc/equivalence_checking/local_clifford_eq.py	92.8%	24 Missing ⚠️
...rc/mqt/qecc/equivalence_checking/permutation_eq.py	96.4%	10 Missing ⚠️

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