lib/gnss: RMC, GGA, GSA and GSV into one GnssState: Fix type, position,
altitude, speed, course, HDOP, UTC time (trusted only with a Fix) and the
satellites in view across constellations. GSV sequences are kept per
constellation and signal band and merged per satellite with the stronger
SNR; GSA's system ID marks which satellites are used. 16 tests, using
lines captured from the device.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT
