Add message discouraging chessboard usage

[tqpcharlie]

Description

I added a warning to inform teams that the 8x8 chessboard can cause bad calibration results, and that the chArUco board should be used instead.

This is my first time contributing to this repo, so please let me know if there's anywhere else I should add this warning. 😄

This PR closes #1515.

Meta

Merge checklist:

• Pull Request title is short, imperative summary of proposed changes
• The description documents the what and why
• If this PR changes behavior or adds a feature, user documentation is updated
• If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• If this PR touches configuration, this is backwards compatible with settings back to v2025.3.2
• If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• If this PR addresses a bug, a regression test for it is added

[samfreund]

Looking good!

Nitpick: this PR has different capitalization for charuco than we typically use. If you want to go through and change capitalization everywhere else, feel free to do so. Otherwise, just change your capitalization to follow what we typically do.

Also, if you can run the linting, that would be great.