- /testcall: plays 3 tones (440/880/660Hz) to test speaker - /testecho: mic → speaker loopback with 100ms delay (/stopecho to end) - /testmic: records 3 seconds, plays back (tests both mic + speaker) No relay or peer needed — pure local browser audio. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>