fix: "без категории" filter matches rooms with undefined categoryId

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

src/pages/RoomsPage.tsx

@@ -46,7 +46,8 @@ export function RoomsPage() {
       r.type.toLowerCase().includes(search.toLowerCase()) ||
       (r.name ?? '').toLowerCase().includes(search.toLowerCase())
     const matchFloor = floorFilter === 'all' || r.floor === floorFilter
-    const matchCat   = categoryFilter === 'all' || r.categoryId === categoryFilter
+    const matchCat   = categoryFilter === 'all' ||
+      (categoryFilter === '' ? !r.categoryId : r.categoryId === categoryFilter)
     return matchSearch && matchFloor && matchCat
   })