New tools: mccoplot folder_A/ folder_B/

[willend]

Free-form text area

Please describe what your PR is adding in terms of features or bugfixes:

New tools to allow co-plotting 1D curves from two similar datasets. Supplements the mcplot and mcplotdiff tools.

Comes in 3 flavours:

• mccoplot-html
• mccoplot-pyqtgraph (aka mccoplot)
• mccoplot-matplotlib

Style of usage / plotting etc. similar to the other tools.

A few consequence-edits to the diffplotters due to the new incoming tools.

Tools have been tested functional across variant as well as operating system. Some minor tweaks still incoming, especially for the HTML tools.

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Declaration of use of AI-tools

• Please add a checkmark here if you used AI-tools during the work for this contribution
• Furter, please describe how / where and for what the tools were used:

Continuation of earlier Claude session for mcplotdiff etc.

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Development OS / boundary conditions

Please describe what OS you developed and tested your additions on, and if any special dependencies are required:

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PR Checklist for contributing to McStas/McXtrace

For a coherent and useful contribution to McStas/McXtrace, please fill in relevant parts of the checklist:

• My contribution contains something else

  • Explanation is added in free form text above or below the checklist

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