Bounded blocking queue simulation

Simulate a bounded blocking queue with one producer and one consumer over discrete ticks. The queue has capacity 'cap'. events is a list of strings, one per tick, each 'P' (producer attempts to enqueue one item) or 'C' (consumer attempts to dequeue one item). A 'P' that finds the queue full is BLOCKED (no item added, counts as a blocked-produce). A 'C' that finds the queue empty is BLOCKED (counts as a blocked-consume). Successful operations change the queue size. Return [items_consumed, blocked_produces, blocked_consumes, final_queue_size].