Function make_agent_workspace_directory 

pub fn make_agent_workspace_directory(
    config: &Config,
    agent_alias: &str,
    raw: &str,
) -> Result<(), BrowseError>

Create a directory under the agent’s workspace. Idempotent — if the path already exists as a directory, returns Ok. Rejects path traversal and refuses to create over an existing file or to overwrite a protected top-level file path.