Multiplexing under loss

Both grids load 100 tiles at once over a single connection — left over HTTP/2 (h2-only.r3dakted.net, TCP), right over HTTP/3 (quic-demo, QUIC). Apply real packet loss to port 443 and watch HTTP/2 stall in head-of-line waves while HTTP/3 keeps filling. Loss is applied to the whole site for the duration of a run.