Add a dedicated error type for direct url parsing. This change is broken
out from the new uv requirement type, which uses direct url parsing
internally.
## 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
I noticed in #2769 that I was now stripping `.git` suffixes from Git
URLs after resolving to a precise commit. This PR cleans up the internal
caching to use a better canonical representation: a `RepositoryUrl`
along with a `GitReference`, instead of a `GitUrl` which can contain
non-canonical data. This gives us both better fidelity (preserving the
`.git`, along with any casing that the user provided when defining the
URL) and is overall cleaner and more robust.
## Summary
This PR leverages our lookahead direct URL resolution to significantly
improve the range of Git URLs that we can accept (e.g., if a user
provides the same requirement, once as a direct dependency, and once as
a tag). We did some of this in #2285, but the solution here is more
general and works for arbitrary transitive URLs.
Closes https://github.com/astral-sh/uv/issues/2614.