docs: Generative AI use policy

[Vuks69]

A policy needs to be set in place for contributions that are assisted by generative AI.

Proposed approach: similar to what Torvalds adopted for the Linux kernel.

https://github.com/torvalds/linux/blob/master/Documentation/process/coding-assistants.rst
https://github.com/torvalds/linux/blob/master/Documentation/process/generated-content.rst

Core idea

Blanket banning AI contributions will not work - users may lie about their contributions and introduce more workload for maintainers, as well as potentially bad code slipping by reviewers unaware that it was vibe-coded with little understanding of it by the PR author.

Allowing AI-assisted contributions but requiring them to be marked as such:

• reduces the risk of contributors lying about it (since there's virtually no reward for it anymore)
• alerts maintainers to pay extra caution to such contributions, reducing risk of bad code being merged

As long as you know what you're adding, reviewed what is being changed and have tested it, I think you have proved that it's a well executed commit

In my opinion following a major FOSS project's approach is a better idea than reinventing the wheel and going through the same process they did before coming to the current status quo.