Add support for fault equivalent rewrites

[lunarr-eclipse]

This PR adds support for fault equivalent rewrites, alongside additional documentation and bugfixes.

Changes:

• Implemented fault-equivalent (FE) rewrite mode with toggle button and fault-weight input. This can be accessed in the proof panel.
• Added existing FE rewrites from PyZX to ZXLive
• Added new rewrites to PyZX, which are also supported in ZXLive with this PR: 2FE unfuse-n and fuse-4/5/n
• Bug fixes: vertex dragging, copy 0/π spider rule, typing
• New documentation for shortcuts and FE rewrites

Co-authored with @loisdelamar

[jvdwetering]

Looks great! Could you take a look at the mypy errors? I think not all of them have to do with the new functionality, but some of them probably do.

[RazinShaikh]

@lunarr-eclipse @loisdelamar Can you please fix the merge conflicts and the failing checks? It would be good to merge this before it diverges too much from the main branch.

[96-LB]

Hi @RazinShaikh, since this PR is on my fork and seems to be going stale, I took some time to fix the merge conflicts so that it can be properly tested. I also ran pytest, mypy, and ruff locally. There's still a mypy error, but master is also failing so it seems unrelated to this PR.

I didn't work on this feature at all during the project, but if you need help reviewing I can take a look at the code and/or make any updates as needed.