feat: Add process package to monorepo

- 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.

Cargo.toml

@@ -11,7 +11,7 @@ categories = ["os", "filesystem", "api-bindings"]
 readme = "README.md"
 
 [workspace]
-members = [".", "vault", "git", "redisclient", "mycelium", "text", "os", "net", "zinit_client"]
+members = [".", "vault", "git", "redisclient", "mycelium", "text", "os", "net", "zinit_client", "process"]
 
 [dependencies]
 hex = "0.4"
@@ -66,6 +66,7 @@ sal-text = { path = "text" }
 sal-os = { path = "os" }
 sal-net = { path = "net" }
 sal-zinit-client = { path = "zinit_client" }
+sal-process = { path = "process" }
 
 # Optional features for specific OS functionality
 [target.'cfg(unix)'.dependencies]