feat(android): MiniPlayer TrackActions kebab + shell-level snackbar

Closes the deferred MiniPlayer follow-up from the TrackActions slice.
MiniPlayer gains a TrackActionsButton next to play/pause with
hideQueueActions=true (the playing track is the queue entry itself).

Shell architecture: ShellScaffold now takes navController + owns a
shell-scoped SnackbarHost backed by a TrackActionsViewModel
hiltViewModel() at the shell level. Snackbars triggered by the
MiniPlayer's kebab surface there; per-screen kebabs continue to
flow through each screen's own Scaffold SnackbarHost (independent
collectors so the two never compete).

All 14 ShellScaffold call sites in MinstrelNavGraph updated to pass
navController; mechanical sweep.

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

android/app/src/main/java/com/fabledsword/minstrel/nav/MinstrelNavGraph.kt

@@ -60,42 +60,42 @@ private fun NavGraphBuilder.inShellTopLevel(
     expandPlayer: () -> Unit,
 ) {
     composable<Home> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             HomeScreen(navController = navController)
         }
     }
     composable<Library> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             LibraryScreen(navController = navController)
         }
     }
     composable<Search> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             SearchScreen(navController = navController)
         }
     }
     composable<Discover> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             DiscoverScreen(navController = navController)
         }
     }
     composable<Playlists> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             PlaylistsListScreen(navController = navController)
         }
     }
     composable<Settings> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             SettingsScreen(navController = navController)
         }
     }
     composable<Admin> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             AdminLandingScreen(navController = navController)
         }
     }
     composable<Requests> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             RequestsScreen(navController = navController)
         }
     }
@@ -106,32 +106,32 @@ private fun NavGraphBuilder.inShellDetail(
     expandPlayer: () -> Unit,
 ) {
     composable<AlbumDetail> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             AlbumDetailScreen(navController = navController)
         }
     }
     composable<ArtistDetail> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             ArtistDetailScreen(navController = navController)
         }
     }
     composable<PlaylistDetail> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             PlaylistDetailScreen(navController = navController)
         }
     }
     composable<AdminRequests> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             AdminRequestsScreen(navController = navController)
         }
     }
     composable<AdminQuarantine> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             AdminQuarantineScreen(navController = navController)
         }
     }
     composable<AdminUsers> {
-        ShellScaffold(onExpandPlayer = expandPlayer) {
+        ShellScaffold(navController = navController, onExpandPlayer = expandPlayer) {
             AdminUsersScreen(navController = navController)
         }
     }

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

@@ -32,6 +32,7 @@ import com.composables.icons.lucide.Lucide
 import com.composables.icons.lucide.Music
 import com.composables.icons.lucide.Pause
 import com.composables.icons.lucide.Play
+import com.fabledsword.minstrel.shared.widgets.trackactions.TrackActionsButton
 import com.fabledsword.minstrel.theme.FabledSwordFlatTokens
 
 private const val MINI_BAR_HEIGHT_DP = 64
@@ -77,6 +78,8 @@ private fun MiniCover(coverUrl: String, contentDescription: String) {
 @Composable
 fun MiniPlayer(
     onExpandClick: () -> Unit,
+    onNavigateToAlbum: (String) -> Unit,
+    onNavigateToArtist: (String) -> Unit,
     modifier: Modifier = Modifier,
     viewModel: PlayerViewModel = hiltViewModel(),
 ) {
@@ -122,6 +125,14 @@ fun MiniPlayer(
                     tint = MaterialTheme.colorScheme.onSurface,
                 )
             }
+            // hideQueueActions=true: the playing track is itself the
+            // queue entry, so Play next / Add to queue would be silly.
+            TrackActionsButton(
+                track = track,
+                hideQueueActions = true,
+                onNavigateToAlbum = onNavigateToAlbum,
+                onNavigateToArtist = onNavigateToArtist,
+            )
         }
     }
 }

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

@@ -4,14 +4,26 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.navigation.NavHostController
+import com.fabledsword.minstrel.nav.AlbumDetail
+import com.fabledsword.minstrel.nav.ArtistDetail
 import com.fabledsword.minstrel.player.ui.MiniPlayer
+import com.fabledsword.minstrel.shared.widgets.trackactions.TrackActionsViewModel
 
 /**
  * Outer shell wrapper for "in-app" routes — banners on top
  * (conditional, none implemented yet), routed screen filling the
  * middle, MiniPlayer pinned at the bottom (auto-hides when no track).
+ * A shell-scoped SnackbarHost above the MiniPlayer surfaces transient
+ * messages emitted by the MiniPlayer's TrackActionsButton (snackbars
+ * for in-screen kebabs continue to live on each screen's own Scaffold).
  *
  * Mirrors the Flutter `_ShellWithPlayerBar` (lib/shared/routing.dart).
  *
@@ -21,15 +33,24 @@ import com.fabledsword.minstrel.player.ui.MiniPlayer
  * intentionally do NOT — they fill the entire screen, often with a
  * back-only AppBar.
  *
- * `onExpandPlayer` is the navigate-to-NowPlaying callback; passed
- * through to MiniPlayer so it doesn't have to know the nav graph.
+ * [onExpandPlayer] is the navigate-to-NowPlaying callback passed
+ * through to MiniPlayer's tap-handler. [navController] is needed by
+ * the MiniPlayer kebab for go-to-album / go-to-artist nav.
  */
 @Composable
 fun ShellScaffold(
+    navController: NavHostController,
     onExpandPlayer: () -> Unit,
     modifier: Modifier = Modifier,
+    trackActionsViewModel: TrackActionsViewModel = hiltViewModel(),
     content: @Composable () -> Unit,
 ) {
+    val snackbarHostState = remember { SnackbarHostState() }
+    LaunchedEffect(Unit) {
+        trackActionsViewModel.transientMessages.collect { msg ->
+            snackbarHostState.showSnackbar(msg)
+        }
+    }
     Column(modifier = modifier.fillMaxSize()) {
         // Banners (VersionTooOld, UpdateBanner) live here once those
         // mechanisms exist; for now the slot is empty so the layout
@@ -37,6 +58,11 @@ fun ShellScaffold(
         Box(modifier = Modifier.fillMaxWidth().weight(1f)) {
             content()
         }
-        MiniPlayer(onExpandClick = onExpandPlayer)
+        SnackbarHost(hostState = snackbarHostState)
+        MiniPlayer(
+            onExpandClick = onExpandPlayer,
+            onNavigateToAlbum = { id -> navController.navigate(AlbumDetail(id)) },
+            onNavigateToArtist = { id -> navController.navigate(ArtistDetail(id)) },
+        )
     }
 }