fix(ui): keep the album grid working outside the Random list

Hoisting the shown-seed ref into AlbumList made the prop mandatory in practice:
ArtistShow renders the same grid through ReferenceManyField and passes no seed
tracking, so useRollChanged dereferenced undefined and the artist page died with
"Cannot read properties of undefined (reading 'current')".

Own a ref in the grid when none is passed. A caller with no roll to track then
behaves as it did before, while the Random list keeps the ref that has to outlive
the refresh remount.

ui/src/album/AlbumGridView.jsx

@@ -1,4 +1,4 @@
-import React from 'react'
+import React, { useRef } from 'react'
 import {
   GridList,
   GridListTile,
@@ -239,9 +239,12 @@ const AlbumGridView = ({
   shownSeed,
   ...props
 }) => {
+  // ArtistShow renders this grid too, with no roll to track, so own a ref when none is passed.
+  const ownSeed = useRef(null)
   // A re-roll replaces every album, so the previous roll must not linger while it loads.
   const rerolling =
-    useRollChanged(shownSeed, seed, loading) && albumListType === 'random'
+    useRollChanged(shownSeed ?? ownSeed, seed, loading) &&
+    albumListType === 'random'
   const hide = rerolling || !props.data || !props.ids
   return hide ? <Loading /> : <LoadedAlbumGrid {...props} />
 }

ui/src/album/AlbumGridView.test.jsx

@@ -0,0 +1,18 @@
+import { render } from '@testing-library/react'
+import { describe, it, expect, vi } from 'vitest'
+import AlbumGridView from './AlbumGridView'
+
+// react-admin's Link/useListContext need a router and a store; the grid body is not under test here.
+vi.mock('react-admin', () => ({
+  linkToRecord: () => '/album/1',
+  useListContext: () => ({}),
+  Loading: () => <div data-testid="loading" />,
+}))
+describe('AlbumGridView', () => {
+  // ArtistShow renders the grid through ReferenceManyField, which passes no seed tracking.
+  it('renders without a shownSeed ref', () => {
+    expect(() =>
+      render(<AlbumGridView data={{}} ids={[]} basePath="/album" width="md" />),
+    ).not.toThrow()
+  })
+})