feat: support check-in time ranges for hotel accommodations

- Add check_in_end column to day_accommodations (Migration 102)
- Server: create/update accommodation accepts check_in_end
- Bidirectional sync: check_in_end synced between accommodation
  and linked reservation metadata (check_in_end_time)
- DayDetailPanel: shows check-in range (e.g. "14:00 – 22:00"),
  new "Until" time picker in hotel form
- ReservationModal: new check-in-until field for hotel bookings
- ReservationsPanel: displays check-in range in metadata cells
- i18n: checkInUntil keys in all 15 languages

Closes #366

server/src/db/migrations.ts

@@ -1610,6 +1610,11 @@ function runMigrations(db: Database.Database): void {
     () => {
       db.prepare("UPDATE addons SET enabled = 1 WHERE id = 'naver_list_import'").run();
     },
+
+    // Migration 102: Add check_in_end column for check-in time ranges
+    () => {
+      try { db.exec('ALTER TABLE day_accommodations ADD COLUMN check_in_end TEXT'); } catch (err: any) { if (!err.message?.includes('duplicate column name')) throw err; }
+    },
   ];
 
   if (currentVersion < migrations.length) {