[Communication] Agent communication requires non-ideality

[Joseph0120]

1. Add Mailbox component with PQ, delay model, and Send(...) + Update()
2. Route current event invocations through Mailbox instead of direct callbacks
3. Implement Mailbox on interceptors and execute existing functions
4. Messages are delayed stochastically based on distance
5. No direct event invocation for reassignment/assignment; all go through mailbox
6. PQ is used for scheduling delivery