fix(flutter): artist albums grid — 3 per row, title wraps, no overflow

AlbumCard gains optional `width` (default 140 keeps horizontal lists
unchanged) and `titleMaxLines` (default 1) so callers can let the
title wrap to a second line. Cover sizes to width - 16 instead of a
hardcoded 124, so the card scales down cleanly when a narrower cell
width is passed in.

Artist detail grid: switch to 3 columns. LayoutBuilder computes the
cell width from the available width so AlbumCard sizes to the cell
exactly (no overflow). cellH = cover + gap + 2-line title + artist
line + small fudge — tight enough that there's no visible gap below
the card, tall enough to fit a wrapped title.

flutter_client/lib/library/artist_detail_screen.dart

@@ -81,27 +81,38 @@ class ArtistDetailScreen extends ConsumerWidget {
           albums.when(
             error: (e, _) => Center(child: Text('$e', style: TextStyle(color: fs.error))),
             loading: () => const Padding(padding: EdgeInsets.all(16), child: Center(child: CircularProgressIndicator())),
-            data: (list) => GridView.builder(
-              shrinkWrap: true,
-              physics: const NeverScrollableScrollPhysics(),
-              padding: const EdgeInsets.all(8),
-              // mainAxisExtent locks each cell's height to the actual
-              // AlbumCard footprint (124 cover + 8 + 14 title + 12
-              // artist + ~6 padding), instead of letting
-              // childAspectRatio inflate it. Removes the visible vertical
-              // gap below each card.
-              gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
-                crossAxisCount: 2,
-                mainAxisExtent: 168,
-                mainAxisSpacing: 8,
-                crossAxisSpacing: 8,
-              ),
-              itemCount: list.length,
-              itemBuilder: (_, i) {
-                final AlbumRef album = list[i];
-                return AlbumCard(album: album, onTap: () => context.push('/albums/${album.id}'));
-              },
-            ),
+            data: (list) => LayoutBuilder(builder: (ctx, constraints) {
+              const cols = 3;
+              const sidePad = 8.0;
+              const gap = 8.0;
+              final cellW =
+                  (constraints.maxWidth - sidePad * 2 - gap * (cols - 1)) /
+                      cols;
+              // Card content: cover (cellW - 16) + 8 + title (≤2 lines
+              // ≈ 36) + artist line ≈ 16 + small fudge.
+              final cellH = (cellW - 16) + 8 + 36 + 16 + 4;
+              return GridView.builder(
+                shrinkWrap: true,
+                physics: const NeverScrollableScrollPhysics(),
+                padding: const EdgeInsets.fromLTRB(sidePad, 0, sidePad, 16),
+                gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
+                  crossAxisCount: cols,
+                  mainAxisExtent: cellH,
+                  mainAxisSpacing: gap,
+                  crossAxisSpacing: gap,
+                ),
+                itemCount: list.length,
+                itemBuilder: (_, i) {
+                  final AlbumRef album = list[i];
+                  return AlbumCard(
+                    album: album,
+                    width: cellW,
+                    titleMaxLines: 2,
+                    onTap: () => context.push('/albums/${album.id}'),
+                  );
+                },
+              );
+            }),
           ),
         ]),
       ),