fix(android): extract MiniCover from MiniPlayer body (detekt LongMethod)

MiniPlayer body hit 66 lines after the AsyncImage branch added in
f3ee182. Pulled the cover Box into its own MiniCover composable —
takes coverUrl + contentDescription, identical surfaceVariant
background + Lucide.Music fallback as before. MiniPlayer body
drops back to ~45 lines.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/minstrel/player/ui/MiniPlayer.kt

@@ -38,6 +38,32 @@ private const val MINI_BAR_HEIGHT_DP = 64
 private const val MINI_BAR_TONAL_ELEVATION_DP = 4
 private const val COVER_SIZE_DP = 48
 
+@Composable
+private fun MiniCover(coverUrl: String, contentDescription: String) {
+    Box(
+        modifier = Modifier
+            .size(COVER_SIZE_DP.dp)
+            .clip(RoundedCornerShape(FabledSwordFlatTokens.radiusSm))
+            .background(MaterialTheme.colorScheme.surfaceVariant),
+        contentAlignment = Alignment.Center,
+    ) {
+        if (coverUrl.isEmpty()) {
+            Icon(
+                imageVector = Lucide.Music,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        } else {
+            AsyncImage(
+                model = coverUrl,
+                contentDescription = contentDescription,
+                modifier = Modifier.size(COVER_SIZE_DP.dp),
+                contentScale = ContentScale.Crop,
+            )
+        }
+    }
+}
+
 /**
  * Collapsed player bar shown above the bottom nav. Returns nothing
  * when no track is loaded so it doesn't take screen space on a
@@ -69,28 +95,7 @@ fun MiniPlayer(
             modifier = Modifier.padding(horizontal = 12.dp),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            Box(
-                modifier = Modifier
-                    .size(COVER_SIZE_DP.dp)
-                    .clip(RoundedCornerShape(FabledSwordFlatTokens.radiusSm))
-                    .background(MaterialTheme.colorScheme.surfaceVariant),
-                contentAlignment = Alignment.Center,
-            ) {
-                if (track.coverUrl.isEmpty()) {
-                    Icon(
-                        imageVector = Lucide.Music,
-                        contentDescription = null,
-                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
-                    )
-                } else {
-                    AsyncImage(
-                        model = track.coverUrl,
-                        contentDescription = track.title,
-                        modifier = Modifier.size(COVER_SIZE_DP.dp),
-                        contentScale = ContentScale.Crop,
-                    )
-                }
-            }
+            MiniCover(coverUrl = track.coverUrl, contentDescription = track.title)
             Spacer(Modifier.width(12.dp))
             Column(modifier = Modifier.weight(1f)) {
                 Text(