feat(slint): favorites tabs as history pages + homologated nav-bar/title

Each favorites tab is now its own history entry (NavEntry::Favorites{tab},
mirroring Discover) recorded from both the header nav and the in-view tab
bar, so back/forward moves between tabs instead of exiting Favorites. Add
the back/forward NavButtons at the same position as every other page
(11px top padding + 22px gap) — FavoritesView was the only view missing
it — and shrink the "Favorites" heading to Typography.section (the album
name size in AlbumView).

cc

crates/qbz-slint/src/main.rs

@@ -465,6 +465,18 @@ fn apply_entry(
                 ensure_for_you_loaded(runtime, weak, handle, image_cache);
             }
         }
+        nav::NavEntry::Favorites { tab } => {
+            if let Some(fav_tab) = favorites::FavTab::from_tab_id(&tab) {
+                navigate_favorites(
+                    runtime.clone(),
+                    weak.clone(),
+                    handle,
+                    image_cache.clone(),
+                    fav_tab,
+                    &tab,
+                );
+            }
+        }
         nav::NavEntry::Settings => {
             let _ = weak.upgrade_in_event_loop(|w| {
                 w.global::<NavState>().set_view(ContentView::Settings);
@@ -2476,7 +2488,12 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             }
             if let Some(tab) = favorites::FavTab::from_route(route.as_str()) {
                 let tab_id = route.strip_prefix("favorites-").unwrap_or("tracks");
-                nav::record(nav::NavEntry::Home); // favorites is not yet a history entry
+                nav::record(nav::NavEntry::Favorites {
+                    tab: tab_id.to_string(),
+                });
+                if let Some(w) = weak.upgrade() {
+                    update_nav_flags(&w);
+                }
                 navigate_favorites(
                     runtime.clone(),
                     weak.clone(),
@@ -2948,6 +2965,12 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                     }
                     return;
                 };
+                // Each favorites tab is its own history page (mirrors the
+                // Discover tabs) so back/forward moves between them.
+                nav::record(nav::NavEntry::Favorites { tab: id.to_string() });
+                if let Some(w) = weak.upgrade() {
+                    update_nav_flags(&w);
+                }
                 navigate_favorites(
                     runtime.clone(),
                     weak.clone(),

crates/qbz-slint/src/nav.rs

@@ -19,6 +19,12 @@ pub enum NavEntry {
     Discover {
         tab: String,
     },
+    /// A Library > Favorites tab page ("tracks" | "albums" | "artists" |
+    /// "playlists" | "labels"). Each tab is its own history entry so
+    /// back/forward moves between the favorites pages, mirroring Discover.
+    Favorites {
+        tab: String,
+    },
     /// A Qobuz mix detail page ("daily" | "weekly" | "fav" | "top").
     Mix {
         kind: String,

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

@@ -22,6 +22,7 @@ import { AlbumCard } from "../discover/AlbumCard.slint";
 import { TrackRow } from "../primitives/TrackRow.slint";
 import { QbzIcon } from "../primitives/QbzIcon.slint";
 import { LoadingSpinner } from "../primitives/LoadingSpinner.slint";
+import { NavButtons } from "../shell/NavButtons.slint";
 
 // One tab in the favorites tab bar.
 component FavTab inherits Rectangle {
@@ -256,15 +257,26 @@ export component FavoritesView inherits Rectangle {
             width: parent.width;
             padding-left: 32px;
             padding-right: 32px;
-            padding-top: 20px;
+            padding-top: 11px;
             padding-bottom: 100px;
             spacing: 0px;
             alignment: start;
 
+            // Back / forward nav buttons — same position as every other
+            // page (11px top padding, then a 22px gap to the header).
+            HorizontalLayout {
+                alignment: start;
+                NavButtons { }
+            }
+
+            Rectangle { height: 22px; }
+
+            // 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.title;
+                font-size: Typography.section;
                 font-weight: Typography.bold;
             }