feat: TTLockPage — import locks from TTHotel XLS file

- Parse .xls/.xlsx via SheetJS (xlsx package)
- Auto-match Door Name → room number; unmatched rows kept with empty room
- Preview table: green=matched, amber=unmatched, grey=already mapped
- Per-row room dropdown for manual correction before import
- room_id nullable in room_lock_mappings (migration 052)
- Conflict key changed from (hotel_id, room_id) to (hotel_id, lock_mac)
- LEFT JOIN in GET room-locks to show unmatched locks
- DELETE by UUID or MAC depending on whether room is assigned

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

backend/migrations/052_ttlock_nullable_room.sql

@@ -0,0 +1,18 @@
+-- TTLock: room_id в room_lock_mappings становится необязательным
+-- Нужно для импорта замков из TTHotel без привязки к номеру в системе
+
+ALTER TABLE room_lock_mappings
+  ALTER COLUMN room_id DROP NOT NULL;
+
+-- Добавляем lock_name если не было
+ALTER TABLE room_lock_mappings
+  ADD COLUMN IF NOT EXISTS lock_name TEXT;
+
+-- Уникальность теперь по lock_mac (один MAC — одна запись)
+-- Старый unique(hotel_id, room_id) оставляем (работает с NULL через NULLS NOT DISTINCT в PG15+
+-- или просто убираем и заменяем на lock_mac)
+ALTER TABLE room_lock_mappings
+  DROP CONSTRAINT IF EXISTS room_lock_mappings_hotel_id_room_id_key;
+
+ALTER TABLE room_lock_mappings
+  ADD CONSTRAINT room_lock_mappings_hotel_id_lock_mac_key UNIQUE (hotel_id, lock_mac);