feat(slint): wire playlist queue/play-next + toast confirm on enqueue

Playlist cards (carousels, search, favorites) emitted ("playlist","queue")
and ("playlist","play-next") but no handler existed, so the menu items
were dead. Add enqueue_playlist (fetch the playlist's tracks by id and
append, or insert-next in reverse to keep order) and the two match arms.
The album/track enqueue paths already worked but gave no visible feedback
when the queue panel was closed, reading as "unwired" — add a success
toast (Added to queue / Playing next) to every enqueue path.

cc

crates/qbz-slint/src/main.rs

@@ -2694,6 +2694,20 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                         playback::play_tracks(runtime, weak, handle, tracks, 0);
                     });
                 }
+                ("playlist", "queue") => playback::enqueue_playlist(
+                    runtime.clone(),
+                    weak.clone(),
+                    handle.clone(),
+                    id,
+                    false,
+                ),
+                ("playlist", "play-next") => playback::enqueue_playlist(
+                    runtime.clone(),
+                    weak.clone(),
+                    handle.clone(),
+                    id,
+                    true,
+                ),
                 ("playlist", "favorite") => {
                     // Favorite/unfavorite the open playlist.
                     if let Some(w) = weak.upgrade() {

crates/qbz-slint/src/playback.rs

@@ -1015,7 +1015,7 @@ pub fn play_album_radio(
 }
 
 /// Enqueue an album's tracks at the end of the current queue.
-pub fn enqueue_album(runtime: Runtime, _weak: slint::Weak<AppWindow>, handle: tokio::runtime::Handle, album_id: String) {
+pub fn enqueue_album(runtime: Runtime, weak: slint::Weak<AppWindow>, handle: tokio::runtime::Handle, album_id: String) {
     handle.spawn(async move {
         let album = match runtime.core().get_album(&album_id).await {
             Ok(album) => album,
@@ -1043,6 +1043,7 @@ pub fn enqueue_album(runtime: Runtime, _weak: slint::Weak<AppWindow>, handle: to
         }
         runtime.core().add_tracks(tracks).await;
         refresh_sidebar(false);
+        crate::toast::success_weak(&weak, "Added to queue");
     });
 }
 
@@ -1053,7 +1054,7 @@ pub fn enqueue_album(runtime: Runtime, _weak: slint::Weak<AppWindow>, handle: to
 /// sequence — mirroring Tauri's `v2_add_tracks_to_queue_next`.
 pub fn enqueue_album_next(
     runtime: Runtime,
-    _weak: slint::Weak<AppWindow>,
+    weak: slint::Weak<AppWindow>,
     handle: tokio::runtime::Handle,
     album_id: String,
 ) {
@@ -1087,11 +1088,12 @@ pub fn enqueue_album_next(
             runtime.core().add_track_next(track).await;
         }
         refresh_sidebar(false);
+        crate::toast::success_weak(&weak, "Playing next");
     });
 }
 
 /// Enqueue a single track at the end of the current queue.
-pub fn enqueue_track(runtime: Runtime, _weak: slint::Weak<AppWindow>, handle: tokio::runtime::Handle, track_id: u64) {
+pub fn enqueue_track(runtime: Runtime, weak: slint::Weak<AppWindow>, handle: tokio::runtime::Handle, track_id: u64) {
     handle.spawn(async move {
         let track = match runtime.core().get_track(track_id).await {
             Ok(track) => track,
@@ -1117,13 +1119,14 @@ pub fn enqueue_track(runtime: Runtime, _weak: slint::Weak<AppWindow>, handle: to
             make_queue_track(&track, &album_id, &album_title, &album_artist, &album_artwork);
         runtime.core().add_track(queue_track).await;
         refresh_sidebar(false);
+        crate::toast::success_weak(&weak, "Added to queue");
     });
 }
 
 /// Insert a single track immediately after the current track ("Play next").
 pub fn play_track_next(
     runtime: Runtime,
-    _weak: slint::Weak<AppWindow>,
+    weak: slint::Weak<AppWindow>,
     handle: tokio::runtime::Handle,
     track_id: u64,
 ) {
@@ -1152,6 +1155,71 @@ pub fn play_track_next(
             make_queue_track(&track, &album_id, &album_title, &album_artist, &album_artwork);
         runtime.core().add_track_next(queue_track).await;
         refresh_sidebar(false);
+        crate::toast::success_weak(&weak, "Playing next");
+    });
+}
+
+/// Enqueue a whole playlist (by id) at the end of the queue, or immediately
+/// after the current track when `next`. Fetches the playlist's tracks fresh,
+/// so it works from any playlist CARD (carousels, search, favorites) — not just
+/// the currently-open PlaylistView. Mirrors the album enqueue paths.
+pub fn enqueue_playlist(
+    runtime: Runtime,
+    weak: slint::Weak<AppWindow>,
+    handle: tokio::runtime::Handle,
+    playlist_id: String,
+    next: bool,
+) {
+    let Ok(pid) = playlist_id.parse::<u64>() else {
+        return;
+    };
+    handle.spawn(async move {
+        let playlist = match runtime.core().get_playlist(pid).await {
+            Ok(playlist) => playlist,
+            Err(e) => {
+                log::error!("[qbz-slint] playback: enqueue get_playlist {pid} failed: {e}");
+                return;
+            }
+        };
+        let tracks: Vec<QueueTrack> = playlist
+            .tracks
+            .as_ref()
+            .map(|container| container.items.as_slice())
+            .unwrap_or_default()
+            .iter()
+            .map(|track| {
+                let (album_id, album_title, album_artwork) = track
+                    .album
+                    .as_ref()
+                    .map(|a| {
+                        (
+                            a.id.clone(),
+                            a.title.clone(),
+                            a.image.best().cloned().unwrap_or_default(),
+                        )
+                    })
+                    .unwrap_or_default();
+                let album_artist = track
+                    .performer
+                    .as_ref()
+                    .map(|p| p.name.clone())
+                    .unwrap_or_default();
+                make_queue_track(track, &album_id, &album_title, &album_artist, &album_artwork)
+            })
+            .collect();
+        if tracks.is_empty() {
+            return;
+        }
+        if next {
+            // Reverse so the inserted block keeps the playlist's order.
+            for track in tracks.into_iter().rev() {
+                runtime.core().add_track_next(track).await;
+            }
+        } else {
+            runtime.core().add_tracks(tracks).await;
+        }
+        refresh_sidebar(false);
+        crate::toast::success_weak(&weak, if next { "Playing next" } else { "Added to queue" });
     });
 }