fix(web): restore album-page back link; loosen test matchers

The initial Task 13 pass dropped the back-chevron link above the hero
to satisfy a strict getByRole('link', {name: /Miles Davis/}) matcher
that was finding both the back link and the inline hero-artist link.

Better fix: keep the back affordance users expect, and use matchers
that accept ambiguity — getAllByRole for the hero check, and a
strict '^← …' regex for the back-link assertion.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/src/routes/albums/[id]/+page.svelte

@@ -35,6 +35,13 @@
     <LibrarySkeleton variant="album" />
   {:else if query.data}
     {@const album = query.data}
+    <a
+      href={`/artists/${album.artist_id}`}
+      class="text-sm text-text-secondary hover:text-text-primary"
+    >
+      ← {album.artist_name}
+    </a>
+
     <header class="flex flex-col gap-4 md:flex-row md:items-end">
       <img
         src={album.cover_url}

web/src/routes/albums/[id]/album.test.ts

@@ -50,7 +50,11 @@ describe('album detail page', () => {
     render(AlbumPage);
 
     expect(screen.getByRole('heading', { level: 1 })).toHaveTextContent('Kind of Blue');
-    expect(screen.getByRole('link', { name: /Miles Davis/ })).toHaveAttribute('href', '/artists/md');
+    // Two links point at /artists/md: the back chevron and the inline hero link.
+    // getAllByRole returns both; both should target the artist page.
+    const artistLinks = screen.getAllByRole('link', { name: /Miles Davis/ });
+    expect(artistLinks.length).toBeGreaterThanOrEqual(1);
+    artistLinks.forEach((l) => expect(l).toHaveAttribute('href', '/artists/md'));
     expect(screen.getByText(/1959/)).toBeInTheDocument();
     expect(screen.getByText(/2 tracks/i)).toBeInTheDocument();
 
@@ -71,7 +75,9 @@ describe('album detail page', () => {
     };
     (createAlbumQuery as ReturnType<typeof vi.fn>).mockReturnValue(mockQuery({ data: detail }));
     render(AlbumPage);
-    const back = screen.getByRole('link', { name: /Miles Davis/ });
+    // Back chevron specifically (disambiguated from the inline artist link by
+    // the leading arrow character).
+    const back = screen.getByRole('link', { name: /^← Miles Davis/ });
     expect(back).toHaveAttribute('href', '/artists/md');
   });