Drives two real iroh endpoints on localhost (relay disabled, addresses
exchanged directly) through the full production path: reactive connect_peer
with lower-id dialing, sequenced broadcast, receive_datagrams, and
JitterBuffer decode at a realistic mixer cadence. Verifies datagrams arrive
attributed to the sender, the sequence header round-trips, and Opus decodes
to full 20ms frames -- without needing a mic, speakers, or the GUI.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>