Adds haversineKm, extractTrackpoints, isNearTrack, buildJourneySegments, and
addJourneySegments to the shared MapLibre GL IIFE. Updates MapUtils export to
expose the new functions. ES5-only; no arrow functions, const/let, or modules.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WPJztrVGbwic2xTG7G9fjM