## 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.
When parsing requirements from any source, directly parse the url parts
(and reject unsupported urls) instead of parsing url parts at a later
stage. This removes a bunch of error branches and concludes the work
parsing url parts once and passing them around everywhere.
Many usages of the assembled `VerbatimUrl` remain, but these can be
removed incrementally.
Please review commit-by-commit.
## Summary
Rather than storing the `redirects` on the resolver, this PR just
re-uses the "convert this URL to precise" logic when we convert to a
`Resolution` after-the-fact. I think this is a lot simpler: it removes
state from the resolver, and simplifies a lot of the hooks around
distribution fetching (e.g., `get_or_build_wheel_metadata` no longer
returns `(Metadata23, Option<Url>)`).
## Summary
This PR ensures that we expand environment variables _before_ sniffing
for the URL scheme (e.g., `file://` vs. `https://` vs. something else).
Closes https://github.com/astral-sh/uv/issues/2375.
Charlie Marsh
konsti