the fork to cover the space left by incomplete markers is probably not correctly constructed

[BurntSushi]

Whenever we have incomplete marker expressions that provoke a fork, we create an extra fork that spans the negation of the union of those marker expressions. I believe the way we are creating that fork today is not quite correct:

https://github.com/astral-sh/uv/blob/af66f75980ad06ac5801ae4ed2417a2ef1dd209b/crates/uv-resolver/src/resolver/mod.rs#L2557-L2563

Namely, it has no dependencies in it, but I believe it should have all dependencies except for the dependencies that provoked the fork in the first place. That is, it should have every "non fork package" in it:

https://github.com/astral-sh/uv/blob/af66f75980ad06ac5801ae4ed2417a2ef1dd209b/crates/uv-resolver/src/resolver/mod.rs#L2547-L2551

I believe this is the cause of one aspect of the problem reported in #5161.