The relay now answers a stateless ping with pong. The Relay card auto-checks on appear and address changes, showing latency or the connection error; this verifies the endpoint speaks the share protocol, not just that a TCP port is open.
The SwiftUI app bundles the Go swarm engine through gomobile, so an iPhone is a real peer using the existing PAKE handshake, chunk verification, and relay fallback. XcodeGen builds the project and devicectl installs it on the paired phone.
TZGyn