feat: configurable bed types via BedTypesContext

- Add BedTypesContext with default types + add/remove/update operations
- Replace hardcoded BED_ITEM_TYPES array in RoomModal with useBedTypes()
- Add "Справочник спальных мест" section to RoomCategoriesPage
  (expandable, same UX as amenities: add icon+label, rename, delete)
- BedItem.type changed from union to string for dynamic support

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

src/types/index.ts

@@ -51,7 +51,7 @@ export type BedType = 'single' | 'double' | 'queen' | 'king' | 'twin'
 export type BedItemType = 'single' | 'double' | 'queen' | 'king' | 'twin' | 'sofa' | 'bunk' | 'cot'
 
 export interface BedItem {
-  type: BedItemType
+  type: string
   count: number
 }