Expose API on workflow directly

Enable calling the workflow mutation directly - if it isn't arguments from the workflow component, it will just pass through those calls to the workflow.

start is awkward b/c it requires passing the handle to the function, similar to migration definitions.

operations: status, suspendStatus (which is nice b/c it has the status validators), start, cancel

Also suggested here: https://github.com/get-convex/workflow/issues/19#issuecomment-2773657161