createRoute, updateRoute, createActivity, createRouteFromActivity, and
the demo-bot each re-implemented the same choreography after
validateGpx: flatten tracks into [lon, lat] coords for writeGeom and
derive distance / elevation / dayBreaks / description / start time.
The stat derivation lived in a private computeRouteStats in
routes.server.ts that activities couldn't reach, so the two sides had
drifted (activities re-derived inline, with its own start-time logic).
processGpx() in gpx-save.server.ts now owns the whole step: parse +
validate (GpxValidationError as before), coords extraction, and stat
derivation, returning the parsed GpxData so nothing re-parses.
Callers keep their own precedence rules between derived and
caller-supplied stats — routes let explicit input win wholesale, the
activities importer prefers GPX distance unless it is zero. Extends
ADR-0006: the gpx-save module remains the only place that understands
GPX-to-database derivation.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>