Allow naming of `shelljob` tasks

[edan-bainglass]

See comments in code below

def shelljob(
    *,
    command: str,
    name: Optional[str] = None,  # <- add this, or `identifier`
    arguments: Optional[List[str]] = None,
    nodes: Optional[Dict[str, Any]] = None,
    filenames: Optional[Dict[str, str]] = None,
    outputs: Optional[List[Union[str, Dict[str, Any]]]] = None,
    parser: Optional[Callable] = None,
    parser_outputs: Optional[SocketSpec | List[str]] = None,
    metadata: Optional[Dict[str, Any]] = None,
    resolve_command: bool = True,
):
    """Create a ShellJob node in the active WorkGraph and return its outputs handle.

    Usage:
        with WorkGraph(name="test_shell_date_with_arguments") as wg:
            outs = shelljob(command="date", arguments=["--iso-8601"])  # returns handle
            wg.run()
    """
    spec = _build_shelljob_TaskSpec(
        identifier=name,  # <- add this, which this function already accepts
        outputs=outputs, 
        parser_outputs=parser_outputs,
    )

    handle = TaskHandle(spec)
    return handle(
        command=command,
        arguments=arguments,
        nodes=nodes,
        filenames=filenames,
        outputs=outputs,
        parser=parser,
        metadata=metadata,
        resolve_command=resolve_command,
    )