Reorder whole days and insert a day (#589) (#1148)

* feat(days): reorder whole days and insert a day at a position

Adds reorderDays + insertDay to the day service and a PUT /days/reorder route
(plus an optional position on create). Day rows stay stable so a day's
assignments, notes, bookings and accommodations ride along by id; on a dated
trip the calendar dates stay pinned to their slots while the content moves
across them, and each booking's date is re-stamped onto its day's new date
(time-of-day preserved) so day_id stays consistent. Renumbering uses the
two-phase write to avoid the UNIQUE(trip_id, day_number) collision, and a move
that would invert an accommodation's check-in/out span is rejected.

* feat(planner): reorder days from a toolbar popup, and add days

A new toolbar button opens a popup listing the days; drag a row by its grip or
use the up/down arrows to reorder, and add a day from there. Reorders apply
optimistically with rollback and sync over WebSocket; the day headers are left
untouched, so the existing place drop-targets are unaffected.

* i18n: add day-reorder strings across all languages

client/src/store/slices/remoteEventHandler.ts

@@ -283,6 +283,15 @@ export function handleRemoteEvent(set: SetState, get: GetState, event: WebSocket
           dayNotes: newDayNotes,
         }
       }
+      case 'day:reordered': {
+        // Apply the new order instantly when we know all ids; the authoritative
+        // dates + re-stamped booking times are pulled by the refresh below.
+        const orderedIds = payload.orderedIds as number[] | undefined
+        if (!orderedIds || orderedIds.length !== state.days.length) return {}
+        const byId = new Map(state.days.map(d => [d.id, d]))
+        if (!orderedIds.every(id => byId.has(id))) return {}
+        return { days: orderedIds.map((id, i) => ({ ...byId.get(id)!, day_number: i + 1 })) }
+      }
 
       // Day Notes
       case 'dayNote:created': {
@@ -442,6 +451,16 @@ export function handleRemoteEvent(set: SetState, get: GetState, event: WebSocket
     }
   })
 
+  // A reorder/insert re-pins dates and re-stamps booking times server-side, so
+  // pull the authoritative days + reservations for collaborators.
+  if (type === 'day:reordered') {
+    const tripId = get().trip?.id
+    if (tripId) {
+      get().refreshDays(tripId)
+      get().loadReservations(tripId)
+    }
+  }
+
   // Write the change through to IndexedDB using the post-update state
   writeToDexie(type, payload as Record<string, unknown>, get())
 }