Synchronous path + rendering for the surface/waytype breakdown:
- map-core `computeSurfaceBreakdown(coords, surfaces, highways)` → distance-
weighted metres per surface + waytype category (unit-tested);
- `SurfaceBreakdownSchema` in @trails-cool/api;
- nullable `surfaceBreakdown` jsonb on routes + activities;
- Planner `SaveToJournalButton` computes it from the BRouter waytags already in
routeData and sends it; `api.save-to-journal` forwards it; the journal route
callback validates + persists (journal is the authoritative validator);
- `SurfaceBreakdown` component (stacked bars per dimension, map-core palettes,
legend category · % · km largest-first, unknown → "other", hidden when empty)
on route + activity detail; journal gains a @trails-cool/map-core dep;
- i18n journal.surface.* (en + de).
Phase 2 (async Overpass backfill + SSE for imports/uploads, and the e2e that
seeds a breakdown) follows in a separate PR.
Tests: computeSurfaceBreakdown unit (map-core 36); SurfaceBreakdown component
(jsdom, journal 326). typecheck + lint green; verified in the browser.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>