fix(tours): count a multi-day tour in the activity sums only once all its stages are on days

The activity sums never read which stage a day holds, so a multi-day tour
counted its whole route on the last dated stage day while other stages
were on no day yet, and a recording on one stage took the place of the
whole plan beside it. With stages on days of their own, the route now
counts once every stage is on a dated day of the user's, on the last of
them, and is uncounted until then; a recording counts as what was done
and the plan is not added beside it.

server/src/db/repositories/TourActivities.repository.ts

@@ -52,6 +52,8 @@ export interface TourStatsExecutionRow {
   trip_title: string;
   assignment_id: number | null;
   date: string | null;
+  /** MDT-02: the stage of a multi-day tour the day holds, by the key of its first stop; null for the whole tour. */
+  tour_stage_key: string | null;
   participant_count: number;
   joined: number;
 }
@@ -192,6 +194,7 @@ export class TourActivitiesRepository extends TrekRepository<TourActivities> {
         'tr.title as trip_title',
         'da.id as assignment_id',
         'd.date as date',
+        'da.tour_stage_key as tour_stage_key',
         eb
           .selectFrom('assignment_participants as ap')
           .select(eb.fn.countAll<number>().as('n'))