feat(tours): check a city walk's stops off for the day it is on (CW-03)

The walk's detail opened from a day lists its stops in order, each with its
stay, importance and protection, and marks one visited or skipped for that
day, or takes it back. The day row shows how many were visited. Marks reach
the other travellers at once and change no route, place or order; a copy or
another day starts with none.

client/src/api/tourVisits.ts

@@ -0,0 +1,17 @@
+import type { TourVisitListResponse, TourVisitUpdateRequest } from '@trek/shared';
+import apiClient from './client';
+
+/** CW-03: the stations of a trip's city walks visited or skipped on their days. */
+export const tourVisitsApi = {
+  list: (tripId: number | string): Promise<TourVisitListResponse> =>
+    apiClient.get(`/trips/${tripId}/tour-visits`).then((r) => r.data),
+  update: (
+    tripId: number | string,
+    assignmentId: number,
+    stationKey: string,
+    body: TourVisitUpdateRequest
+  ): Promise<TourVisitListResponse> =>
+    apiClient
+      .put(`/trips/${tripId}/tour-visits/${assignmentId}/${encodeURIComponent(stationKey)}`, body)
+      .then((r) => r.data),
+};

client/src/api/wsEventPolicy.ts

@@ -19,6 +19,8 @@ export const HANDLED_OUTSIDE_TRIP_STORE = [
   // Tours facet invalidation — hooks/useTripWebSocket forwards tours:changed to
   // useTourPlaceIds so the active trip refreshes its Tours/Places read model.
   'tours:changed',
+  // CW-03 — components/Tours/walk/useTourVisitsSync keeps the visits store current.
+  'tours:visits',
   // Collab — Collab/MCollab components + useTripWebSocket's collabFileSync
   'collab:note:created',
   'collab:note:updated',