docs: describe project structure

src/features/map/map-service.ts

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+import type { RoutePoint } from "../../domain/route.js";
+
+export function buildRoute(points: RoutePoint[]): RoutePoint[] {
+  return points.slice().sort((a, b) => a.capturedAt.localeCompare(b.capturedAt));
+}
+

src/features/photos/photo-service.ts

@@ -0,0 +1,6 @@
+import type { Photo } from "../../domain/photo.js";
+
+export function listPhotos(): Photo[] {
+  return [];
+}
+