- Ping button: pings all servers via native QUIC, saves RTT + fingerprint
to SharedPreferences, then exits process (System.exit)
- On restart: loads saved ping results (no native .so loading needed)
- Avoids jemalloc crash: native lib only loaded once per process lifetime
- Removed broken UDP probe (QUIC servers don't respond to it)
- SettingsRepository: savePingRtt/loadPingRtt for cached results
- PingResult: added reachable field
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>