feat(tours): give a tour its start and end in the day plan

A tour on a day had no place in the day's timeline: its time was not tied
to the slot it was planned in, so several hikes on one day could not be
lined up. A tour now sits there the way a place does, on the times of its
day entry, one model for every tour type. With a start and a known time
(the planned total, else the estimate of an import) its end follows as the
start plus that time; it is shown fainter, marked with an approximate sign
where it comes from an estimate, and says in its tooltip how it was worked
out. An end typed by hand wins. A day that holds one stage of a multi-day
tour gets no end from the whole route.

When the end runs past the start of the day's next timed item, the row
says so in one quiet line, as a late connection between two city walks
does; nothing is moved. The existing time fields of the day entry, on the
desktop form and the phone sheet, say what the end works out to while none
is typed. City walks keep their arrivals per station. The logic lives in
one module both day plans run on.

client/scripts/feature-pairs.json

@@ -586,6 +586,12 @@
       "desktop": ["src/components/Planner/DayPlanSidebar.tsx"],
       "mobile": ["src/mobile/screens/trip/plan/useMPlanTimeline.ts"]
     },
+    {
+      "feature": "A tour's start and end in the day plan, its end worked out from its time, and an end that runs into the next timed item",
+      "hooks": ["src/components/Tours/tourDayTime.ts"],
+      "desktop": ["src/components/Planner/DayPlanSidebar.tsx"],
+      "mobile": ["src/mobile/screens/trip/plan/useMPlanTimeline.ts"]
+    },
     {
       "feature": "Reservation form incl. hotel accommodation creation",
       "hooks": ["src/components/Planner/reservationFormModel.ts", "src/components/Planner/useReservationForm.ts"],