They specifically ask not to create/submit a formal proposal. I do not see any restriction on the use of AI otherwise.

i read the emphasized "human-written" part, in combination with that last line, as a blanket restriction (for contributing). but perhaps i read it wrong.

The point is that they just want your prompts, not your code.

List of commits already include at least two contributors who are openly working with Claude on their code: https://github.com/yc-software/qm/commits/main/