feat(android): now-playing row highlight on track surfaces

Audit v2 priority #9. Track rows on AlbumDetail, PlaylistDetail,
LikedTab, HistoryTab, and SearchScreen now render the currently-
playing track's title in accent (primary) color so the user can
spot "this is what's playing" while scrolling a list.

Pattern: each screen pulls a PlayerViewModel via hiltViewModel(),
reads state.currentTrack?.id, threads it through to its track row
composable as nowPlaying: Boolean. Row picks titleColor based on
the flag. No new infrastructure — just a thread-through.

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

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

@@ -100,8 +100,11 @@ fun HistoryTab(
     onNavigateToAlbum: (String) -> Unit = {},
     onNavigateToArtist: (String) -> Unit = {},
     viewModel: HistoryTabViewModel = hiltViewModel(),
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel = hiltViewModel(),
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
+    val playerState by playerViewModel.uiState.collectAsStateWithLifecycle()
+    val playingTrackId = playerState.currentTrack?.id
     PullToRefreshScaffold(onRefresh = { viewModel.refresh().join() }) {
         when (val s = state) {
             HistoryUiState.Loading -> LoadingCentered()
@@ -115,6 +118,7 @@ fun HistoryTab(
             )
             is HistoryUiState.Success -> HistoryList(
                 entries = s.entries,
+                playingTrackId = playingTrackId,
                 onPlay = viewModel::playTrack,
                 onNavigateToAlbum = onNavigateToAlbum,
                 onNavigateToArtist = onNavigateToArtist,
@@ -126,6 +130,7 @@ fun HistoryTab(
 @Composable
 private fun HistoryList(
     entries: List<HistoryEntry>,
+    playingTrackId: String?,
     onPlay: (TrackRef) -> Unit,
     onNavigateToAlbum: (String) -> Unit,
     onNavigateToArtist: (String) -> Unit,
@@ -134,6 +139,7 @@ private fun HistoryList(
         items(items = entries, key = { it.id }) { entry ->
             HistoryRow(
                 entry = entry,
+                nowPlaying = entry.track.id == playingTrackId,
                 onClick = { onPlay(entry.track) },
                 onNavigateToAlbum = onNavigateToAlbum,
                 onNavigateToArtist = onNavigateToArtist,
@@ -146,10 +152,16 @@ private fun HistoryList(
 @Composable
 private fun HistoryRow(
     entry: HistoryEntry,
+    nowPlaying: Boolean,
     onClick: () -> Unit,
     onNavigateToAlbum: (String) -> Unit,
     onNavigateToArtist: (String) -> Unit,
 ) {
+    val titleColor = if (nowPlaying) {
+        MaterialTheme.colorScheme.primary
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
     Row(
         modifier = Modifier
             .fillMaxWidth()
@@ -163,7 +175,7 @@ private fun HistoryRow(
             Text(
                 text = entry.track.title,
                 style = MaterialTheme.typography.bodyLarge,
-                color = MaterialTheme.colorScheme.onSurface,
+                color = titleColor,
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
             )

android/app/src/main/java/com/fabledsword/minstrel/library/ui/AlbumDetailScreen.kt

@@ -67,6 +67,7 @@ fun AlbumDetailScreen(
     navController: NavHostController,
     viewModel: AlbumDetailViewModel = hiltViewModel(),
     trackActionsViewModel: TrackActionsViewModel = hiltViewModel(),
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel = hiltViewModel(),
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     val snackbarHostState = remember { SnackbarHostState() }
@@ -102,10 +103,12 @@ fun AlbumDetailScreen(
                 is AlbumDetailUiState.Success -> {
                     val albumLiked by viewModel.albumLiked.collectAsStateWithLifecycle()
                     val likedTrackIds by viewModel.likedTrackIds.collectAsStateWithLifecycle()
+                    val playerState by playerViewModel.uiState.collectAsStateWithLifecycle()
                     AlbumBody(
                         detail = s.detail,
                         albumLiked = albumLiked,
                         likedTrackIds = likedTrackIds,
+                        playingTrackId = playerState.currentTrack?.id,
                         onPlayAll = { viewModel.play(startTrackId = null) },
                         onShuffleAll = viewModel::shuffle,
                         onTrackClick = { id -> viewModel.play(startTrackId = id) },
@@ -130,6 +133,7 @@ private fun AlbumBody(
     detail: AlbumDetailRef,
     albumLiked: Boolean,
     likedTrackIds: Set<String>,
+    playingTrackId: String?,
     onPlayAll: () -> Unit,
     onShuffleAll: () -> Unit,
     onTrackClick: (String) -> Unit,
@@ -156,6 +160,7 @@ private fun AlbumBody(
             TrackRow(
                 track = track,
                 liked = track.id in likedTrackIds,
+                nowPlaying = track.id == playingTrackId,
                 onClick = { onTrackClick(track.id) },
                 onToggleLike = { onToggleTrackLike(track.id) },
                 onNavigateToAlbum = onNavigateToAlbum,
@@ -274,11 +279,17 @@ private fun trackCountLine(album: AlbumRef): String {
 private fun TrackRow(
     track: TrackRef,
     liked: Boolean,
+    nowPlaying: Boolean,
     onClick: () -> Unit,
     onToggleLike: () -> Unit,
     onNavigateToAlbum: (String) -> Unit,
     onNavigateToArtist: (String) -> Unit,
 ) {
+    val titleColor = if (nowPlaying) {
+        MaterialTheme.colorScheme.primary
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
     Row(
         modifier = Modifier
             .fillMaxWidth()
@@ -296,7 +307,7 @@ private fun TrackRow(
             Text(
                 text = track.title,
                 style = MaterialTheme.typography.bodyLarge,
-                color = MaterialTheme.colorScheme.onSurface,
+                color = titleColor,
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
             )

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

@@ -124,8 +124,11 @@ class LikedTabViewModel @Inject constructor(
 fun LikedTab(
     navController: NavHostController,
     viewModel: LikedTabViewModel = hiltViewModel(),
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel = hiltViewModel(),
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
+    val playerState by playerViewModel.uiState.collectAsStateWithLifecycle()
+    val playingTrackId = playerState.currentTrack?.id
     PullToRefreshScaffold(onRefresh = { viewModel.refresh().join() }) {
         when (val s = state) {
             LikedTabUiState.Loading -> LoadingCentered()
@@ -140,6 +143,7 @@ fun LikedTab(
             )
             is LikedTabUiState.Success -> LikedContent(
                 sections = s.sections,
+                playingTrackId = playingTrackId,
                 onArtistClick = { id -> navController.navigate(ArtistDetail(id)) },
                 onAlbumClick = { id -> navController.navigate(AlbumDetail(id)) },
                 onTrackClick = { index ->
@@ -155,6 +159,7 @@ fun LikedTab(
 @Composable
 private fun LikedContent(
     sections: LikedSections,
+    playingTrackId: String?,
     onArtistClick: (String) -> Unit,
     onAlbumClick: (String) -> Unit,
     onTrackClick: (Int) -> Unit,
@@ -196,6 +201,7 @@ private fun LikedContent(
             itemsIndexed(items = sections.tracks, key = { _, t -> "trk-${t.id}" }) { index, track ->
                 LikedTrackRow(
                     track = track,
+                    nowPlaying = track.id == playingTrackId,
                     onClick = { onTrackClick(index) },
                     onNavigateToAlbum = onNavigateToAlbum,
                     onNavigateToArtist = onNavigateToArtist,
@@ -232,10 +238,16 @@ private fun SectionHeader(label: String, count: Int) {
 @Composable
 private fun LikedTrackRow(
     track: TrackRef,
+    nowPlaying: Boolean,
     onClick: () -> Unit,
     onNavigateToAlbum: (String) -> Unit,
     onNavigateToArtist: (String) -> Unit,
 ) {
+    val titleColor = if (nowPlaying) {
+        MaterialTheme.colorScheme.primary
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
     Row(
         modifier = Modifier
             .fillMaxWidth()
@@ -249,7 +261,7 @@ private fun LikedTrackRow(
             Text(
                 text = track.title,
                 style = MaterialTheme.typography.bodyLarge,
-                color = MaterialTheme.colorScheme.onSurface,
+                color = titleColor,
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
             )

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

@@ -197,6 +197,7 @@ fun PlaylistDetailScreen(
     navController: NavHostController,
     viewModel: PlaylistDetailViewModel = hiltViewModel(),
     trackActionsViewModel: TrackActionsViewModel = hiltViewModel(),
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel = hiltViewModel(),
 ) {
     val state by viewModel.uiState.collectAsState()
     val snackbarHostState = remember { SnackbarHostState() }
@@ -231,9 +232,11 @@ fun PlaylistDetailScreen(
                 is PlaylistDetailUiState.Error -> ErrorBlock(s.message, viewModel::refresh)
                 is PlaylistDetailUiState.Success -> {
                     val likedTrackIds by viewModel.likedTrackIds.collectAsState()
+                    val playerState by playerViewModel.uiState.collectAsState()
                     PlaylistDetailBody(
                         detail = s.detail,
                         likedTrackIds = likedTrackIds,
+                        playingTrackId = playerState.currentTrack?.id,
                         onPlayAll = { viewModel.play(s.detail.tracks, startTrackId = null) },
                         onShuffleAll = {
                             viewModel.play(s.detail.tracks.shuffled(), startTrackId = null)
@@ -262,6 +265,7 @@ private fun currentTitle(state: PlaylistDetailUiState): String = when (state) {
 private fun PlaylistDetailBody(
     detail: PlaylistDetailRef,
     likedTrackIds: Set<String>,
+    playingTrackId: String?,
     onPlayAll: () -> Unit,
     onShuffleAll: () -> Unit,
     onTrackClick: (String) -> Unit,
@@ -279,6 +283,7 @@ private fun PlaylistDetailBody(
             TrackRow(
                 row = row,
                 liked = row.trackId != null && row.trackId in likedTrackIds,
+                nowPlaying = row.trackId != null && row.trackId == playingTrackId,
                 onClick = { row.trackId?.let(onTrackClick) },
                 onToggleLike = { row.trackId?.let(onToggleTrackLike) },
                 onNavigateToAlbum = onNavigateToAlbum,
@@ -389,6 +394,7 @@ private fun PlaylistCover(playlist: PlaylistRef) {
 private fun TrackRow(
     row: PlaylistTrackRef,
     liked: Boolean,
+    nowPlaying: Boolean,
     onClick: () -> Unit,
     onToggleLike: () -> Unit,
     onNavigateToAlbum: (String) -> Unit,
@@ -396,6 +402,11 @@ private fun TrackRow(
 ) {
     val enabled = row.isAvailable
     val rowAlpha = if (enabled) 1f else UNAVAILABLE_ALPHA
+    val baseTitleColor = if (nowPlaying) {
+        MaterialTheme.colorScheme.primary
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
     Row(
         modifier = Modifier
             .fillMaxWidth()
@@ -412,7 +423,7 @@ private fun TrackRow(
             Text(
                 text = row.title,
                 style = MaterialTheme.typography.bodyLarge,
-                color = MaterialTheme.colorScheme.onSurface.copy(alpha = rowAlpha),
+                color = baseTitleColor.copy(alpha = rowAlpha),
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
             )

android/app/src/main/java/com/fabledsword/minstrel/search/ui/SearchScreen.kt

@@ -66,8 +66,11 @@ fun SearchScreen(
     navController: NavHostController,
     viewModel: SearchViewModel = hiltViewModel(),
     trackActionsViewModel: TrackActionsViewModel = hiltViewModel(),
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel = hiltViewModel(),
 ) {
     val state by viewModel.state.collectAsStateWithLifecycle()
+    val playerState by playerViewModel.uiState.collectAsStateWithLifecycle()
+    val playingTrackId = playerState.currentTrack?.id
     val focusRequester = remember { FocusRequester() }
     val snackbarHostState = remember { SnackbarHostState() }
     LaunchedEffect(Unit) { focusRequester.requestFocus() }
@@ -107,6 +110,7 @@ fun SearchScreen(
         Box(modifier = Modifier.fillMaxSize().padding(inner)) {
             ResultsPane(
                 state = state.results,
+                playingTrackId = playingTrackId,
                 onArtistClick = { id -> navController.navigate(ArtistDetail(id)) },
                 onAlbumClick = { id -> navController.navigate(AlbumDetail(id)) },
                 onTrackPlay = viewModel::playTrack,
@@ -144,6 +148,7 @@ private fun SearchField(
 @Composable
 private fun ResultsPane(
     state: SearchResultsState,
+    playingTrackId: String?,
     onArtistClick: (String) -> Unit,
     onAlbumClick: (String) -> Unit,
     onTrackPlay: (TrackRef) -> Unit,
@@ -160,6 +165,7 @@ private fun ResultsPane(
             } else {
                 ResultsList(
                     response = state.response,
+                    playingTrackId = playingTrackId,
                     onArtistClick = onArtistClick,
                     onAlbumClick = onAlbumClick,
                     onTrackPlay = onTrackPlay,
@@ -174,6 +180,7 @@ private fun ResultsPane(
 @Composable
 private fun ResultsList(
     response: SearchResponseRef,
+    playingTrackId: String?,
     onArtistClick: (String) -> Unit,
     onAlbumClick: (String) -> Unit,
     onTrackPlay: (TrackRef) -> Unit,
@@ -186,7 +193,13 @@ private fun ResultsList(
     ) {
         artistsSection(response.artists, onArtistClick)
         albumsSection(response.albums, onAlbumClick)
-        tracksSection(response.tracks, onTrackPlay, onNavigateToAlbum, onNavigateToArtist)
+        tracksSection(
+            response.tracks,
+            playingTrackId,
+            onTrackPlay,
+            onNavigateToAlbum,
+            onNavigateToArtist,
+        )
     }
 }
 
@@ -224,6 +237,7 @@ private fun LazyListScope.albumsSection(
 
 private fun LazyListScope.tracksSection(
     tracks: List<TrackRef>,
+    playingTrackId: String?,
     onTrackPlay: (TrackRef) -> Unit,
     onNavigateToAlbum: (String) -> Unit,
     onNavigateToArtist: (String) -> Unit,
@@ -233,6 +247,7 @@ private fun LazyListScope.tracksSection(
     items(items = tracks, key = { "trk-${it.id}" }) { track ->
         TrackResultRow(
             track = track,
+            nowPlaying = track.id == playingTrackId,
             onClick = { onTrackPlay(track) },
             onNavigateToAlbum = onNavigateToAlbum,
             onNavigateToArtist = onNavigateToArtist,
@@ -244,10 +259,16 @@ private fun LazyListScope.tracksSection(
 @Composable
 private fun TrackResultRow(
     track: TrackRef,
+    nowPlaying: Boolean,
     onClick: () -> Unit,
     onNavigateToAlbum: (String) -> Unit,
     onNavigateToArtist: (String) -> Unit,
 ) {
+    val titleColor = if (nowPlaying) {
+        MaterialTheme.colorScheme.primary
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
     Row(
         modifier = Modifier
             .fillMaxWidth()
@@ -261,7 +282,7 @@ private fun TrackResultRow(
             Text(
                 text = track.title,
                 style = MaterialTheme.typography.bodyLarge,
-                color = MaterialTheme.colorScheme.onSurface,
+                color = titleColor,
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
             )