Support lossless serialization for Git dependencies in lockfile (#3630)

## Summary

This PR adds lossless deserialization for `GitSourceDist` distributions
in the lockfile. Specifically, we now properly preserve the requested
revision, the subdirectory, and the precise Git commit SHA.

## Test Plan

`cargo test`

crates/uv-git/src/sha.rs

@@ -1,7 +1,7 @@
 use std::str::FromStr;
 
 /// A complete Git SHA, i.e., a 40-character hexadecimal representation of a Git commit.
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct GitSha(git2::Oid);
 
 impl GitSha {