Implement run_producer_consumer(capacity, producer_items, num_consumers) that coordinates concurrent producers and consumers through a shared bounded buffer.

Parameters:

• capacity: the maximum number of items the buffer can hold at once (an integer >= 1).
• producer_items: a list where each element is itself a list of items that one producer thread will place into the buffer, in order.
• num_consumers: the number of consumer threads that remove items from the buffer.

Run all producers and all consumers concurrently. A producer that finds the buffer full must wait until space is available; a consumer that finds the buffer empty must wait until an item is available. The function must terminate cleanly once every produced item has been consumed.

Return the list of all consumed items sorted in ascending order. (Sorting is used so the result is deterministic regardless of thread scheduling.)

Constraints:

• Do not use busy-waiting (no spinning loops that repeatedly poll without blocking).
• Avoid deadlocks and lost wakeups.
• Items will never be the value None.