Fix Zustand shallow import

Use Zustand's public shallow selector export so the import page resolves correctly under the installed Zustand 5 package. This fixes the Vite boot overlay without changing import workflow behavior.

webui/src/routes/import/-import.store.ts

@@ -1,6 +1,6 @@
 import { create } from 'zustand';
 import { combine } from 'zustand/middleware';
-import { useShallow } from 'zustand/react/shallow';
+import { useShallow } from 'zustand/shallow';
 
 import type {
   ImportAlbumMatchPayload,