chore: Bump version to v2.18.0

Bluetooth enhancements (service data inspector, appearance codes, MAC
cluster tracking, behavioral flags, IRK badges, distance estimation),
ACARS SoapySDR multi-backend support, dump1090 stale process cleanup,
GPS error state, and proximity radar/signal card UI improvements.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -41,6 +41,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     bluez \
     bluetooth \
     # GPS support
+    gpsd \
     gpsd-clients \
     # Utilities
     # APRS