Implement Command Module

[masa10-f]

Before submitting, please check the following:

• Make sure you have tests for the new code and that test passes (run pytest)
• If applicable, add a line to the [unreleased] part of CHANGELOG.md, following keep-a-changelog.
• Format added code by ruff
• Type checking by mypy and pyright
• Make sure the checks (github actions) pass.
• Check that the docs compile without errors (run make html in ./docs/ - you may need to install dependency for sphinx docs, see docs/requirements.txt.)

Then, please fill in below:

Description of the change:

• Added command.py module, which has basic operations in MBQC.
• Added D command, which expresses the decoding operation.
• Added decoder_backend.py module. Currently, only the XORDecoder is implemented

Related issue:

[Copilot]

Pull Request Overview

This PR implements a new command module and decoder backend for MBQC operations. Key changes include:

• Adding a new command module with various command classes (N, E, M, X, Z, Clifford, D).
• Implementing the XORDecoder in the decoder backend.
• Adding comprehensive tests for the XORDecoder functionality.

Reviewed Changes

Copilot reviewed 3 out of 6 changed files in this pull request and generated 1 comment.

File	Description
tests/test_decoder_backend.py	Added tests targeting XORDecoder behavior.
graphix_zx/decoder_backend.py	Implemented BaseDecoder and XORDecoder classes.
graphix_zx/command.py	Introduced new command classes including command D.

Files not reviewed (3)

• docs/source/command.rst: Language not supported
• docs/source/decoder_backend.rst: Language not supported
• docs/source/references.rst: Language not supported

Comments suppressed due to low confidence (1)

tests/test_decoder_backend.py:1

• [nitpick] The header comment in this file ('# test_xor_decoder.py') does not match the filename ('test_decoder_backend.py'). Consider updating it for consistency.

# test_xor_decoder.py