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.
## 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.
