Rust: keep dependencies that share a name with a workspace target

[rockwotj]

workspaceArtifacts() drops artifacts by name, using every package and target name from cargo metadata --no-deps. When a workspace target has the same name as a dependency, the dependency's artifacts are dropped too.

In our repository, app/jobserver declares [lib] name = "jobserver", which is also the name of the crates.io jobserver crate that cc depends on. The saved archive left out libjobserver-<hash>.rlib and .fingerprint/jobserver-<hash>, so every warm run rebuilt jobserver, then cc, then every crate that uses cc in a build script (aws-lc-sys, zstd-sys, lz4-sys, libmimalloc-sys, ...) and everything downstream of those: 57 crates instead of the 3 workspace crates.

This change reads the registry and git packages from each root's Cargo.lock and removes their names from the set that is stripped. Workspace artifacts that share such a name are then kept in the archive. They rebuild anyway, so the only cost is archive size.

Measured on tensorlake-large with the same Rust workspace (cargo fmt, clippy, test), warm runs:

	Crates compiled	clippy + test
v1	57	80–92 s
this branch	3	20–25 s

npm test includes a new case with a workspace lib named jobserver and a Cargo.lock that lists the registry crate. It fails on main and passes here.