'moroutine': minor#

Add isTask() type guard for narrowing tasks to a specific moroutine

if (isTask(isPrime, task)) {
  // task: Task<boolean, [n: number]>
  const [n] = task.args;
}

• Moroutines returned by mo() now expose a readonly id for stable identity
• isTask(mo, task) returns true when task was produced by mo, and narrows the task to the descriptor type produced by that moroutine
• Task<T, A>.args is now typed as A (previously unknown[]) so narrowing propagates to argument access — unchanged for Task<T> without a specialized arg tuple