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

shared/src/day/day.schema.ts

@@ -49,9 +49,17 @@ export type Day = z.infer<typeof daySchema>;
 export const dayCreateRequestSchema = z.object({
   date: z.string().optional(),
   notes: z.string().optional(),
+  // 1-based slot to insert a new empty day at (omit to append at the end).
+  position: z.number().int().positive().optional(),
 });
 export type DayCreateRequest = z.infer<typeof dayCreateRequestSchema>;
 
+/** Reorder whole days: the desired full sequence of this trip's day ids. */
+export const dayReorderRequestSchema = z.object({
+  orderedIds: z.array(z.number()),
+});
+export type DayReorderRequest = z.infer<typeof dayReorderRequestSchema>;
+
 export const dayUpdateRequestSchema = z.object({
   notes: z.string().optional(),
   title: z.string().nullable().optional(),