fix: cdn.hotelsync.ru nginx config + RoomModal key for state reset

- Add cdn.hotelsync.ru server block to nginx config (serves /var/www/uploads)
- Add cdn.hotelsync.ru to HTTP redirect server_name
- RoomModal: add key={editingRoom?.id ?? 'new'} to force state reinit on room change
- RoomModal: remove categories[0] fallback for categoryId (show 'Без категории' instead)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/RoomsPage.tsx

@@ -203,8 +203,9 @@ export function RoomsPage() {
         </div>
       )}
 
-      {/* Modal */}
+      {/* Modal — key forces remount so useState reinitializes with the new room */}
       <RoomModal
+        key={editingRoom?.id ?? 'new'}
         open={modalOpen}
         room={editingRoom}
         onClose={() => { setModalOpen(false); setSaveError(null) }}