Sun/Moon rise+set from GPS lat/lon + date (Spencer 1971), moon phase 0-29.
Chronometer with lap times, countdown timer with alarm beep and preset
cycling, altimeter with GPS alt_m, min/max persistence and trend graph.
Swipe left/right to switch tabs. 4 tabs fit any screen size.
test(harness): add 7 ProTreck scenarios (tdeck, v4, no_gps, chrono,
timer, alti, cost). ALL OK 7/7.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
