Lock and resolve with project name where available

[lucab]

This populates the project package name (if available) for lock-and-resolve operations.

[lucab]

Note: drive-by fix, I noticed this detail was missing when looking into a derivation tree result from PubGrub. I think in practice this should be a no-op change for any observable behavior, but I'll let CI check that.

[zanieb]

I believe the PubGrub "root" package is intentionally None when you're working in a project. Instead, the root has a dependency on all of the workspace members. This modeling is important for the resolver in some ways I don't fully understand, but we workaround this in the error reports:

uv/crates/uv-resolver/src/pubgrub/report.rs

Lines 361 to 368 in 5e1b9b1

	if self.is_workspace() {
	if matches!(&**package, PubGrubPackageInner::Root(_)) {
	if self.is_single_project_workspace() {
	return Some("your projects's requirements".to_string());
	}
	return Some("your workspace's requirements".to_string());
	}
	}

uv/crates/uv-resolver/src/error.rs

Lines 619 to 626 in 4ff057e

	/// Given a [`DerivationTree`], drop dependency incompatibilities from the root
	/// to the project.
	///
	/// Intended to effectively change the root to a workspace member in single project
	/// workspaces, avoiding a level of indirection like "And because your project
	/// requires your project, we can conclude that your projects's requirements are
	/// unsatisfiable."
	fn drop_root_dependency_on_project(

I think adding the name here would be confusing, since we'd have Root("my-project") -> Package("my-project") in the tree?

[lucab]

What you say makes plenty of sense in the context of workspaces with packages, and I'm inclined to drop this PR as it may have some side-effect implications that I currently can't fully evaluate.

At the same time, it is notable that this is the only invocation of pip::operations::resolve() explicitly without a project.
All the other 5 occurrences do forward a project name, and in virtually all the cases it seems that the source of that value can be traced back to this:

uv/crates/uv-requirements/src/specification.rs

Lines 229 to 232 in df90cc6

	// Use the first project name discovered.
	if spec.project.is_none() {
	spec.project = source.project;
	}