Blocking queue

A simple blocking FIFO queue and flow control library using Promises, allowing consumers to process tasks with a configurable concurrency limit. Version 0.0.1 is the initial release. It provides a Queue class for push/pop operations and a QueueConsumer to start/stop task processing. Different from full-featured message queues like Bull or Kue, this is lightweight and designed for in-process task orchestration. The library is minimal but functional, suitable for simple sequential or parallel task execution in Node.js.