## Summary
It turns out that the Git fetch implementation is initializing its own
client, which can be really expensive on macOS (due to loading native
certificates) _and_ bypasses any of our middleware. This PR modifies the
Git implementation to accept a shared client.
## Summary
This PR ensures that if a lockfile already contains a resolved reference
(e.g., you locked with `main` previously, and it locked to a specific
commit), and you run `uv lock`, we use the same SHA, even if it's not
the latest SHA for that tag. This avoids upgrading Git dependencies
without `--upgrade`.
Closes#3920.
## Summary
This PR removes the static resolver map:
```rust
static RESOLVED_GIT_REFS: Lazy<Mutex<FxHashMap<RepositoryReference, GitSha>>> =
Lazy::new(Mutex::default);
```
With a `GitResolver` struct that we now pass around on the
`BuildContext`. There should be no behavior changes here; it's purely an
internal refactor with an eye towards making it cleaner for us to
"pre-populate" the list of resolved SHAs.
Charlie Marsh