feat(android): playbar everywhere, song-search context menu, offline tab loads offline

- MiniPlayer now shows on every screen (album/artist/playlist detail), not just
  top-level tabs; the tab bar stays top-level-only.
- Local library song search results get the 3-dot context menu (add to playlist,
  favorite, queue, download, …) via onShowContextMenu.
- Offline tab is fed by the local Room DB and no longer waits on the online library:
  it stays usable while the library is loading or the server is unreachable.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

android/app/src/main/kotlin/com/novasonic/app/ui/AppNavigation.kt

@@ -155,7 +155,8 @@ fun AppNavigation() {
             containerColor = NsBackground,
             modifier = Modifier.background(NsBackground).background(bgGlow),
             bottomBar = {
-                if (isTopLevel) {
+                // MiniPlayer shows on EVERY screen (incl. album/artist/playlist detail) so playback
+                // is always reachable; the tab bar stays top-level-only.
                 Column {
                     // ABS audio routes through MusicService — one notification, one mini player.
                     // When an ABS book is loaded, tapping the mini player opens the ABS overlay
@@ -190,6 +191,7 @@ fun AppNavigation() {
                             },
                         )
                     }
+                    if (isTopLevel) {
                         NavigationBar(containerColor = NavBg, tonalElevation = 0.dp) {
                             navItems.forEach { dest ->
                                 NavigationBarItem(
@@ -272,6 +274,7 @@ fun AppNavigation() {
                         onSongPlay    = { songs, idx -> player.playSongs(songs, idx) },
                         onAlbumClick  = { album -> navController.navigate("album/${album.id}") },
                         onArtistClick = { artist -> navController.navigate("artist/${artist.id}") },
+                        onShowContextMenu = ::showContextMenu,
                         onOpenImporter = { navController.navigate("importer") },
                     )
                 }

android/app/src/main/kotlin/com/novasonic/app/ui/screen/ExploreScreen.kt

@@ -49,6 +49,7 @@ fun ExploreScreen(
     onSongPlay: (List<com.novasonic.app.api.model.Song>, Int) -> Unit,
     onAlbumClick: (com.novasonic.app.api.model.Album) -> Unit,
     onArtistClick: (com.novasonic.app.api.model.Artist) -> Unit,
+    onShowContextMenu: ((com.novasonic.app.api.model.Song) -> Unit)? = null,
     onOpenImporter: () -> Unit = {},
 ) {
     val vm: ExploreViewModel = viewModel()
@@ -214,6 +215,7 @@ fun ExploreScreen(
                 onSongPlay  = onSongPlay,
                 onAlbumClick = onAlbumClick,
                 onArtistClick = onArtistClick,
+                onShowContextMenu = onShowContextMenu,
             )
             ExploreTab.GLOBAL  -> GlobalExploreContent(
                 state        = state,
@@ -238,6 +240,7 @@ private fun LibrarySearchContent(
     onSongPlay: (List<com.novasonic.app.api.model.Song>, Int) -> Unit,
     onAlbumClick: (com.novasonic.app.api.model.Album) -> Unit,
     onArtistClick: (com.novasonic.app.api.model.Artist) -> Unit,
+    onShowContextMenu: ((com.novasonic.app.api.model.Song) -> Unit)? = null,
 ) {
     // Reuse SearchScreen's ViewModel
     val vm: com.novasonic.app.viewmodel.SearchViewModel = viewModel()
@@ -315,7 +318,9 @@ private fun LibrarySearchContent(
                     song     = song,
                     coverUrl = coverUrl(song.coverArt),
                     isPlaying = playerState.currentSong?.id == song.id,
+                    starred  = song.starred != null,
                     onPlay   = { onSongPlay(songs, idx) },
+                    onMore   = onShowContextMenu?.let { cb -> { cb(song) } },
                 )
             }
         }

android/app/src/main/kotlin/com/novasonic/app/ui/screen/LibraryScreen.kt

@@ -108,7 +108,9 @@ fun LibraryScreen(
             }
         }
 
-        if (state.isLoading) {
+        // The Offline tab is fed by the local Room DB (offlineGroups) and must stay usable even while
+        // the online library is still loading or unreachable — only gate the network-backed tabs.
+        if (state.isLoading && state.tab != LibraryTab.OFFLINE) {
             Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
                 CircularProgressIndicator(color = NsAccent)
             }