GPS extraction in gps_export.cpp already finds the first valid fix by
testing lat/lon != 0 and year >= 2000 on actual record data, so the
configurable cold-start skip was never consumed anywhere after pm_findgpslock
was introduced. Removed from:
  - AppSettings struct (lib/config_manager.hpp)
  - getGpsSkip() accessor (lib/config_manager.hpp)
  - loadSettings() / saveSettings() / showSettings() (lib/config_manager.cpp)
  - CLI prefs menu [C] item and handler (cli/prefs.cpp)
  - GUI Settings dialog widget, load, save (gui/SettingsDialog.h/.cpp)

Existing pathmux.json files with the key are silently forward-compatible:
the key is ignored on load and not written back on next save.

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