Track origin for setup.py files and friends (#3481)

## Summary

Ensures that we track the origins for requirements regardless of whether
they come from `pyproject.toml` or `setup.py` or `setup.cfg`.

Closes #3480.

crates/uv-dev/src/resolve_many.rs

@@ -132,7 +132,7 @@ pub(crate) async fn resolve_many(args: ResolveManyArgs) -> Result<()> {
                             extras: requirement.extras,
                             version_or_url: Some(equals_version),
                             marker: None,
-                            source: requirement.source,
+                            origin: requirement.origin,
                         }
                     } else {
                         requirement