🌐 Packet Path Diorama: Queues, Congestion and Adaptive Routing Lab — 2D Network Map and Queue Phase Plane

2D companion of the packet path diorama: a top-down network map with per-cable queues and packets, a utilisation versus queue-length phase plane against the M/M/1 curve, and delay/loss time series. Uses the same discrete-event engine as the 3D version.