feat(slint): favorites tracks Play all + Shuffle header actions

Retain the loaded favorite tracks as a play-ready Vec<Track> and add
Play all + Shuffle CircleAction buttons by the title (Tracks tab only),
wired to playback::play_tracks. Mirrors the Mix/Playlist transport
(those expose exactly these two; no batch play-next path exists yet).

cc

crates/qbz-slint/src/favorites.rs

@@ -8,7 +8,7 @@
 //! relevant branch into typed qbz-models items and maps them to the
 //! Slint row/card structs.
 
-use std::sync::Arc;
+use std::sync::{Arc, LazyLock, Mutex};
 
 use qbz_app::shell::AppRuntime;
 use qbz_core::FrontendAdapter;
@@ -32,6 +32,10 @@ pub const PAGE_SIZE: u32 = 500;
 /// FAVORITES_PAGE_SIZE * FAVORITES_MAX_PAGES ceiling).
 const MAX_ITEMS: usize = 10_000;
 
+/// The loaded favorite tracks as a play-ready queue source (Play all /
+/// Shuffle). Set on the UI thread by `apply_favorites`.
+static FAV_CURRENT: LazyLock<Mutex<Vec<Track>>> = LazyLock::new(|| Mutex::new(Vec::new()));
+
 /// Which favorites tab to load.
 #[derive(Clone, Copy, PartialEq, Eq)]
 pub enum FavTab {
@@ -85,7 +89,7 @@ struct FavLabel {
 }
 
 pub enum FavData {
-    Tracks { items: Vec<TrackCard>, total: usize },
+    Tracks { items: Vec<TrackCard>, play: Vec<Track>, total: usize },
     Albums { items: Vec<AlbumCard>, total: usize },
     Artists { items: Vec<ArtistCard>, total: usize },
     Playlists { items: Vec<PlaylistCard>, total: usize },
@@ -191,8 +195,10 @@ where
     Ok(match tab {
         FavTab::Tracks => {
             let tracks: Vec<Track> = serde_json::from_value(items).unwrap_or_default();
+            let play = tracks.clone();
             FavData::Tracks {
                 items: tracks.into_iter().map(map_track).collect(),
+                play,
                 total,
             }
         }
@@ -308,7 +314,10 @@ fn map_label(label: FavLabel) -> LabelCard {
 pub fn apply_favorites(window: &AppWindow, data: FavData) {
     let state = window.global::<FavoritesState>();
     match data {
-        FavData::Tracks { items, total } => {
+        FavData::Tracks { items, play, total } => {
+            if let Ok(mut current) = FAV_CURRENT.lock() {
+                *current = play;
+            }
             let rows: Vec<TrackItem> = items
                 .into_iter()
                 .map(|t| TrackItem {
@@ -414,6 +423,30 @@ pub fn derive_tracks(window: &AppWindow) {
     state.set_tracks_visible(ModelRc::new(VecModel::from(filtered)));
 }
 
+/// The loaded favorite tracks as a play-ready queue (Play all).
+pub fn play_tracks() -> Vec<Track> {
+    FAV_CURRENT.lock().map(|c| c.clone()).unwrap_or_default()
+}
+
+/// The favorite tracks in a fresh random order (Shuffle). Mirrors
+/// playlist::shuffled_tracks (time-seeded xorshift Fisher-Yates).
+pub fn shuffled_tracks() -> Vec<Track> {
+    let mut tracks = play_tracks();
+    let mut seed = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .map(|d| d.as_nanos() as u64)
+        .unwrap_or(1)
+        | 1;
+    for i in (1..tracks.len()).rev() {
+        seed ^= seed << 13;
+        seed ^= seed >> 7;
+        seed ^= seed << 17;
+        let j = (seed % (i as u64 + 1)) as usize;
+        tracks.swap(i, j);
+    }
+    tracks
+}
+
 pub fn reset_loading(window: &AppWindow) {
     window.global::<FavoritesState>().set_loading(true);
 }

crates/qbz-slint/src/main.rs

@@ -4272,6 +4272,40 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                 }
             });
     }
+    {
+        // Play all favorite tracks as a fresh queue.
+        let runtime = app_runtime.clone();
+        let weak = window.as_weak();
+        let handle = tokio_rt.handle().clone();
+        window
+            .global::<FavoritesActions>()
+            .on_play_all_tracks(move || {
+                playback::play_tracks(
+                    runtime.clone(),
+                    weak.clone(),
+                    handle.clone(),
+                    favorites::play_tracks(),
+                    0,
+                );
+            });
+    }
+    {
+        // Shuffle-play the favorite tracks.
+        let runtime = app_runtime.clone();
+        let weak = window.as_weak();
+        let handle = tokio_rt.handle().clone();
+        window
+            .global::<FavoritesActions>()
+            .on_shuffle_tracks(move || {
+                playback::play_tracks(
+                    runtime.clone(),
+                    weak.clone(),
+                    handle.clone(),
+                    favorites::shuffled_tracks(),
+                    0,
+                );
+            });
+    }
 
     // Artwork right-click menu wiring — Open in browser / Save as /
     // Add custom / Remove custom. Mirrors the v2_library_* + native

crates/qbz-slint/ui/favorites/FavoritesView.slint

@@ -21,6 +21,7 @@ import {
 import { AlbumCard } from "../discover/AlbumCard.slint";
 import { TrackRow } from "../primitives/TrackRow.slint";
 import { ExpandableSearch } from "../primitives/ExpandableSearch.slint";
+import { CircleAction } from "../primitives/CircleAction.slint";
 import { QbzIcon } from "../primitives/QbzIcon.slint";
 import { LoadingSpinner } from "../primitives/LoadingSpinner.slint";
 import { ListScrollbar } from "../primitives/ListScrollbar.slint";
@@ -275,11 +276,43 @@ export component FavoritesView inherits Rectangle {
 
             // Page title — same size as the album name in AlbumView
             // (Typography.section), not the larger Typography.title.
-            Text {
-                text: @tr("Favorites");
-                color: Theme.text-primary;
-                font-size: Typography.section;
-                font-weight: Typography.bold;
+            HorizontalLayout {
+                spacing: 12px;
+                VerticalLayout {
+                    alignment: center;
+                    horizontal-stretch: 1;
+                    Text {
+                        text: @tr("Favorites");
+                        color: Theme.text-primary;
+                        font-size: Typography.section;
+                        font-weight: Typography.bold;
+                    }
+                }
+                // Tracks header actions — Play all + Shuffle the favorites
+                // queue. Shown only when the Tracks tab has rendered rows.
+                if FavoritesState.active-tab == "tracks"
+                    && FavoritesState.tracks-visible.length > 0: HorizontalLayout {
+                    spacing: 8px;
+                    VerticalLayout {
+                        alignment: center;
+                        CircleAction {
+                            icon: @image-url("../assets/icons/play-fill.svg");
+                            primary: true;
+                            clicked => {
+                                FavoritesActions.play-all-tracks();
+                            }
+                        }
+                    }
+                    VerticalLayout {
+                        alignment: center;
+                        CircleAction {
+                            icon: @image-url("../assets/icons/shuffle.svg");
+                            clicked => {
+                                FavoritesActions.shuffle-tracks();
+                            }
+                        }
+                    }
+                }
             }
 
             Rectangle { height: 16px; }

crates/qbz-slint/ui/state.slint

@@ -1477,6 +1477,8 @@ export global FavoritesActions {
     callback play-track(string /* track id */);
     callback track-action(string /* track id */, string /* action */);
     callback search-tracks(string /* query */);
+    callback play-all-tracks();
+    callback shuffle-tracks();
 }
 
 // A Qobuz mix detail page (DailyQ / WeeklyQ / FavQ / TopQ), opened