feat: add thread-safe Queue for TurboAPI handlers

[justrach]

Summary

• Adds Queue, QueueEmpty, QueueFull - a thread-safe in-memory queue that works from Tokio worker threads where asyncio.Queue fails
• Uses threading.Condition + collections.deque for true thread safety across Python 3.13, 3.13t, and 3.14
• Pure Python implementation - works with or without the Rust extension

Usage

from turboapi import Queue, QueueEmpty

task_queue = Queue(maxsize=100)

@app.post("/enqueue")
def enqueue(data: dict):
    task_queue.put(data)
    return {"queued": task_queue.qsize()}

@app.get("/dequeue")
def dequeue():
    try:
        item = task_queue.get(timeout=5.0)
        return {"item": item}
    except QueueEmpty:
        return {"error": "timeout"}, 408

API

• put(item, block=True, timeout=None) / put_nowait(item)
• get(block=True, timeout=None) / get_nowait()
• qsize(), empty(), full()
• task_done(), join(timeout=None)

Test plan

• 20 tests passing: basic ops, non-blocking, timeouts, thread safety, bounded queues, task_done/join