Adds the `user.rust` UPM to workshop-engine for managing Rust
toolchains,
components, cross-compilation targets, and cargo operations:
- `rustup default <toolchain>` / `rustup component add` / `rustup target
add`
- `cargo fetch` for dependency pre-fetch with optional `--locked`
- `cargo install` for global crate tools with registry support
Includes 275-line test suite (`tests/upm/test_rust.py`) covering the
full
lifecycle with optional network tests.
for testability
- Add `ManagedChild` trait abstracting process lifecycle (real
`TokioChild` + `MockChild` for tests)
- Use Unix process groups (`process_group(0)` + `libc::kill(-pgid,
SIGKILL)`) for tree-wide termination
- Remove cgroup-related code (`CgroupManager`, `ResourceUsage`,
`cgroup_path` field)
- Update imports across test files to use `workshop-engine` crate
directly
crate
BREAKING CHANGE: Moved engine/ module (cgroups, executor, pm, upm,
types) and shared types (command, repology, time) from workshop-baker to
new workshop-engine crate. All internal error types consolidated into
workshop-engine::error. Import paths changed throughout codebase.
Catty Steve