feat(android): shared TrackCoverThumb + cover art on Playlist/History rows

Factors the cover-thumbnail composable out of LikedTab into a shared
widget so PlaylistDetail tracks and HistoryTab rows can reuse it.
Same placeholder-URL trick — BaseUrlInterceptor rewrites the host
on every request and Coil shares the OkHttp client.

New:
  - shared/widgets/TrackCoverThumb.kt — composable with size +
    coverUrl + contentDescription params. Defaults to 48dp; passes
    the size through to both the clip and the fallback icon so
    callers can scale up/down without re-implementing.

Modified:
  - models/Playlist.kt — adds `coverUrl` derived prop on
    PlaylistTrackRef. Same `/api/albums/{id}/cover` pattern as
    TrackRef.coverUrl; empty when albumId is null (the
    track-removed-from-library case).
  - likes/ui/LikedTab.kt — drops the local TrackCoverThumb copy,
    uses the shared one. Removes 8 now-unused imports.
  - playlists/ui/PlaylistDetailScreen.kt — adds cover thumb to track
    rows. Drops the leading position number (1, 2, 3...) since row
    order already conveys position and the cover fills that visual
    slot.
  - history/ui/HistoryTab.kt — adds cover thumb leading each
    history row. Vertical padding tightened 10dp → 8dp to match the
    other thumb-bearing rows.

Search track results stay deferred — its TextRow handles
artists/albums/tracks generically, splitting it for per-track
covers is a bigger change.

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

android/app/src/main/java/com/fabledsword/minstrel/history/ui/HistoryTab.kt

@@ -29,6 +29,7 @@ import com.fabledsword.minstrel.history.data.HistoryRepository
 import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.player.PlayerController
 import com.fabledsword.minstrel.shared.widgets.EmptyState
+import com.fabledsword.minstrel.shared.widgets.TrackCoverThumb
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -131,10 +132,11 @@ private fun HistoryRow(entry: HistoryEntry, onClick: () -> Unit) {
         modifier = Modifier
             .fillMaxWidth()
             .clickable(enabled = entry.track.streamUrl.isNotEmpty(), onClick = onClick)
-            .padding(horizontal = 16.dp, vertical = 10.dp),
+            .padding(horizontal = 16.dp, vertical = 8.dp),
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = Arrangement.spacedBy(12.dp),
     ) {
+        TrackCoverThumb(coverUrl = entry.track.coverUrl, contentDescription = entry.track.title)
         Column(modifier = Modifier.weight(1f)) {
             Text(
                 text = entry.track.title,

android/app/src/main/java/com/fabledsword/minstrel/likes/ui/LikedTab.kt

@@ -1,6 +1,5 @@
 package com.fabledsword.minstrel.likes.ui
 
-import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -12,26 +11,18 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
-import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.HorizontalDivider
-import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.draw.clip
-import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
-import coil3.compose.AsyncImage
-import com.composables.icons.lucide.Lucide
-import com.composables.icons.lucide.Music
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
@@ -47,6 +38,7 @@ import com.fabledsword.minstrel.nav.AlbumDetail
 import com.fabledsword.minstrel.nav.ArtistDetail
 import com.fabledsword.minstrel.shared.widgets.EmptyState
 import com.fabledsword.minstrel.shared.widgets.HorizontalScrollRow
+import com.fabledsword.minstrel.shared.widgets.TrackCoverThumb
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
@@ -217,7 +209,7 @@ private fun LikedTrackRow(track: TrackRef) {
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = Arrangement.spacedBy(12.dp),
     ) {
-        TrackCoverThumb(track)
+        TrackCoverThumb(coverUrl = track.coverUrl, contentDescription = track.title)
         Column(modifier = Modifier.weight(1f)) {
             Text(
                 text = track.title,
@@ -237,33 +229,6 @@ private fun LikedTrackRow(track: TrackRef) {
     }
 }
 
-@Composable
-private fun TrackCoverThumb(track: TrackRef) {
-    Box(
-        modifier = Modifier
-            .size(48.dp)
-            .clip(RoundedCornerShape(4.dp))
-            .background(MaterialTheme.colorScheme.surfaceVariant),
-        contentAlignment = Alignment.Center,
-    ) {
-        if (track.coverUrl.isEmpty()) {
-            Icon(
-                imageVector = Lucide.Music,
-                contentDescription = null,
-                tint = MaterialTheme.colorScheme.onSurfaceVariant,
-                modifier = Modifier.size(24.dp),
-            )
-        } else {
-            AsyncImage(
-                model = track.coverUrl,
-                contentDescription = track.title,
-                modifier = Modifier.fillMaxSize(),
-                contentScale = ContentScale.Crop,
-            )
-        }
-    }
-}
-
 @Composable
 private fun LoadingCentered() {
     Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {

android/app/src/main/java/com/fabledsword/minstrel/models/Playlist.kt

@@ -44,4 +44,17 @@ data class PlaylistTrackRef(
     val streamUrl: String? = null,
 ) {
     val isAvailable: Boolean get() = trackId != null
+
+    /**
+     * Cover URL derived from the parent album's `/api/albums/{id}/cover`
+     * endpoint, using the placeholder host that `BaseUrlInterceptor`
+     * rewrites to the live server URL. Same mechanism as
+     * [TrackRef.coverUrl] — Coil shares the OkHttp client. Empty when
+     * the row has no album binding (rare; usually only for tracks
+     * whose upstream album was deleted).
+     */
+    val coverUrl: String
+        get() = albumId?.takeIf { it.isNotEmpty() }
+            ?.let { "http://placeholder.invalid/api/albums/$it/cover" }
+            .orEmpty()
 }

android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistDetailScreen.kt

@@ -61,6 +61,7 @@ import com.fabledsword.minstrel.likes.data.LikesRepository
 import com.fabledsword.minstrel.playlists.data.PlaylistDetailRef
 import com.fabledsword.minstrel.playlists.data.PlaylistsRepository
 import com.fabledsword.minstrel.shared.widgets.LikeButton
+import com.fabledsword.minstrel.shared.widgets.TrackCoverThumb
 import com.fabledsword.minstrel.theme.FabledSwordFlatTokens
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -336,11 +337,10 @@ private fun TrackRow(
             .padding(horizontal = 16.dp, vertical = 8.dp),
         verticalAlignment = Alignment.CenterVertically,
     ) {
-        Text(
-            text = "${row.position}",
-            color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = rowAlpha),
-            style = MaterialTheme.typography.bodySmall,
-            modifier = Modifier.width(28.dp),
+        TrackCoverThumb(
+            coverUrl = row.coverUrl,
+            contentDescription = row.title,
+            modifier = Modifier.padding(end = 12.dp),
         )
         Column(modifier = Modifier.weight(1f)) {
             Text(

android/app/src/main/java/com/fabledsword/minstrel/shared/widgets/TrackCoverThumb.kt

@@ -0,0 +1,66 @@
+package com.fabledsword.minstrel.shared.widgets
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import coil3.compose.AsyncImage
+import com.composables.icons.lucide.Lucide
+import com.composables.icons.lucide.Music
+
+/**
+ * Shared track-row cover thumbnail. Pulls the cover from the track's
+ * derived `coverUrl` (which Coil resolves through the shared OkHttp
+ * + BaseUrlInterceptor); falls back to a Lucide.Music glyph on a
+ * surfaceVariant-tinted background when the URL is empty (album
+ * cover hasn't loaded into the cache yet OR the track has no album
+ * binding).
+ *
+ * Used by LikedTab, PlaylistDetail, HistoryTab, and any other dense
+ * track list. Sizes default to 48dp — the four-corner radius and
+ * fallback-icon size scale with the outer dimension so callers can
+ * pass e.g. 56dp for a more prominent row without re-implementing.
+ */
+@Composable
+fun TrackCoverThumb(
+    coverUrl: String,
+    contentDescription: String?,
+    modifier: Modifier = Modifier,
+    size: Dp = DEFAULT_SIZE,
+) {
+    Box(
+        modifier = modifier
+            .size(size)
+            .clip(RoundedCornerShape(4.dp))
+            .background(MaterialTheme.colorScheme.surfaceVariant),
+        contentAlignment = Alignment.Center,
+    ) {
+        if (coverUrl.isEmpty()) {
+            Icon(
+                imageVector = Lucide.Music,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.size(size / 2),
+            )
+        } else {
+            AsyncImage(
+                model = coverUrl,
+                contentDescription = contentDescription,
+                modifier = Modifier.fillMaxSize(),
+                contentScale = ContentScale.Crop,
+            )
+        }
+    }
+}
+
+private val DEFAULT_SIZE: Dp = 48.dp