feat: add priority task queue with concurrency control

[dsm20]

No description provided.

[github-actions]

Comprehension Gate

Answer the questions below in order to merge.

Q1. When a task is added to the queue using add(fn, { priority }), how is its position determined if multiple tasks have the same priority?

• A) It is always added to the end of the queue, regardless of priority.
• B) It is inserted before the first task with a lower priority; if all existing tasks have equal or higher priority, it's added to the end.
• C) It is inserted after the last task with an equal or higher priority, maintaining a stable order.
• D) The implementation does not guarantee a specific order for tasks with identical priorities; it depends on the iteration order of findIndex.

Q2. What is the primary purpose of the drain() method, and when does it resolve?

• A) It stops all currently running tasks and clears the queue, resolving immediately.
• B) It pauses the queue and resolves when all currently running tasks complete.
• C) It returns a Promise that resolves when all tasks, both running and pending, have completed their execution.
• D) It resolves when the queue is empty, but only if pause() has been called previously.

Q3. Consider a scenario where clear() is called. What happens to tasks that are currently running at the time of the call?

• A) Running tasks are immediately aborted and their promises are rejected.
• B) Running tasks are allowed to complete normally, but their results are discarded, and their promises are neither resolved nor rejected by the queue.
• C) Running tasks continue to execute until completion, and their promises will resolve or reject as usual, independent of the clear() operation.
• D) Running tasks are paused and their execution is resumed if resume() is called later.

---

Reply in a format like this:

1. A
2. C
3. B

Questions are based on commit 02405d7. Pushing new commits regenerates the questions.