Replace WzpEngine.pingRelay() (JNI, loads native .so, crashes jemalloc
on Android 16 MTE) with pure Kotlin DatagramSocket UDP probe.
- RelayPinger: sends QUIC Version Negotiation trigger packet, measures
RTT from response. No native lib, no JNI, zero crash risk.
- Periodic: pings all servers every 5 seconds via coroutine
- Server fingerprint: filled lazily on first real QUIC connection
(TOFU still works, just delayed)
- Lock status: OFFLINE when ping fails, NEW until first connection
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>