Fixes https://github.com/astral-sh/uv/issues/16447
Passing this around explicitly uncovers some behaviors where we pass
e.g. the credentials store to reading the lockfile. The changes in this
PR should preserve the existing behavior for now, they only make the
locations we read from more explicit.
Labeling this PR as "Enhancement" instead of "Internal" in case this
changes behavior when it shouldn't have.
Part of https://github.com/astral-sh/uv/issues/4392
We shouldn't link to PyPI, and dropping the workspace-level
documentation link should mean that we get the auto-generated `docs.rs`
links.
## Summary
Make the use of `Self` consistent. Mostly done by running `cargo clippy
--fix -- -A clippy::all -W clippy::use_self`.
## Test Plan
<!-- How was it tested? -->
No need.
## Summary
If you `uv add` a Git dependency, we resolve it twice:

While we need to avoid sharing state between `lock` and `sync` (see the
large TODO that moved in this change), we should prioritize sharing
state between different resolver operations.
As per
https://matklad.github.io/2021/02/27/delete-cargo-integration-tests.html
Before that, there were 91 separate integration tests binary.
(As discussed on Discord — I've done the `uv` crate, there's still a few
more commits coming before this is mergeable, and I want to see how it
performs in CI and locally).