- Add `sal-process` package for cross-platform process management.
- Update workspace members in `Cargo.toml`.
- Mark process package as complete in MONOREPO_CONVERSION_PLAN.md
- Remove license information from `mycelium` and `os` READMEs.
- Add the `mycelium` package to the workspace members.
- Add `sal-mycelium` dependency to `Cargo.toml`.
- Update MONOREPO_CONVERSION_PLAN.md to reflect the addition
and completion of the mycelium package.