What's new in 1.1.2-rc.3

- Block or mute contacts and channel senders, with a Blocked management screen
- Per-channel notifications: all, mentions only, or muted
- Better path tracing and mesh topology readout
- Share and add channels by QR code
- Fix: USB no longer wedges some ESP32 boards on connect
- Fix: messages to a blocked contact are no longer sent
- More radios report GPS position reliably
