feat(qbz-slint): real Discover Home view

After sign-in the app loads the real Qobuz discover index and renders
the Home view: a time-based greeting with the user's name, the tab
pill (Home / Editor's Picks / For You), and discover sections — New
Releases, Press Accolades, Ideal Discography, Qobuzissimes, Albums of
the Week — each a horizontally scrolling row of album cards.

- state.slint: AlbumCardItem / DiscoverSection structs, HomeState global.
- discover/: AlbumCard (artwork area, award ribbon, title, artist,
  quality badge), SectionRow, HomeView.
- home.rs: discover-index fetch and mapping (award-ribbon priority,
  quality string), greeting, and event-loop model application. Unit
  tests for ribbon, quality, and greeting logic.
- AppShell content region is now the HomeView.

Album artwork images load in the next increment (artwork pipeline);
cards currently show the elevated placeholder. No fixtures — all data
is the live discover index.

cc

crates/qbz-slint/ui/app.slint

@@ -8,6 +8,9 @@ import { Theme } from "foundation/semantic-colors.slint";
 import { LoginScreen } from "login/LoginScreen.slint";
 import { AppShell } from "shell/AppShell.slint";
 
+// Re-export the HomeState global so the Rust layer can populate it.
+export { HomeState } from "state.slint";
+
 // Which top-level screen is shown. During M1 the screen switches on a
 // login-button click without real authentication; M2 ties the switch
 // to a real session.

crates/qbz-slint/ui/discover/AlbumCard.slint

@@ -0,0 +1,107 @@
+// Album card for the Discover sections.
+//
+// Mirrors the Svelte AlbumCardLite: 220px column, square artwork with a
+// bottom-left award ribbon, single-line title, artist, and a compact
+// quality badge. Artwork image loading lands in the artwork-pipeline
+// increment; for now the artwork area is the same elevated placeholder
+// the real card shows before its image resolves.
+
+import { Theme } from "../foundation/semantic-colors.slint";
+import { Typography } from "../foundation/typography.slint";
+import { Radius } from "../foundation/radius.slint";
+import { Spacing } from "../foundation/spacing.slint";
+import { AlbumCardItem } from "../state.slint";
+
+export component AlbumCard inherits Rectangle {
+    in property <AlbumCardItem> album;
+
+    width: 220px;
+    height: 282px;
+
+    VerticalLayout {
+        spacing: Spacing.xs;
+
+        // --- Artwork ------------------------------------------------------
+        Rectangle {
+            width: 220px;
+            height: 220px;
+            border-radius: Radius.sm;
+            background: Theme.surface-elevated;
+            clip: true;
+
+            if root.album.ribbon != "": Rectangle {
+                x: 0px;
+                y: parent.height - self.height - 8px;
+                height: 20px;
+                background: root.album.ribbon-kind == "press"
+                    ? #d49511
+                    : #000000e0;
+                border-top-right-radius: 3px;
+                border-bottom-right-radius: 3px;
+
+                // Left accent stripe (not on the gold press ribbon).
+                Rectangle {
+                    x: 0px;
+                    width: root.album.ribbon-kind == "press" ? 0px : 3px;
+                    background: root.album.ribbon-kind == "qobuzissime"
+                        ? #8b5cf6
+                        : #eab308;
+                }
+                HorizontalLayout {
+                    padding-left: 10px;
+                    padding-right: 10px;
+                    Text {
+                        text: root.album.ribbon;
+                        color: root.album.ribbon-kind == "press"
+                            ? #1f1407
+                            : #ffffff;
+                        font-size: 10px;
+                        font-weight: Typography.semibold;
+                        vertical-alignment: center;
+                        overflow: elide;
+                    }
+                }
+            }
+        }
+
+        // --- Title --------------------------------------------------------
+        Text {
+            text: root.album.title;
+            color: Theme.text-primary;
+            font-size: Typography.body;
+            font-weight: Typography.medium;
+            overflow: elide;
+        }
+
+        // --- Artist + quality --------------------------------------------
+        HorizontalLayout {
+            spacing: Spacing.sm;
+
+            Text {
+                text: root.album.artist;
+                color: Theme.text-muted;
+                font-size: Typography.link;
+                vertical-alignment: center;
+                overflow: elide;
+                horizontal-stretch: 1;
+            }
+
+            if root.album.quality != "": Rectangle {
+                background: Theme.surface-elevated;
+                border-radius: 3px;
+                HorizontalLayout {
+                    padding-left: 6px;
+                    padding-right: 6px;
+                    padding-top: 3px;
+                    padding-bottom: 3px;
+                    Text {
+                        text: root.album.quality;
+                        color: Theme.text-secondary;
+                        font-size: 9px;
+                        vertical-alignment: center;
+                    }
+                }
+            }
+        }
+    }
+}

crates/qbz-slint/ui/discover/HomeView.slint

@@ -0,0 +1,86 @@
+// Discover — Home view: greeting, tab pill, and the discover sections.
+//
+// Section data is supplied by the Rust home controller through the
+// HomeState global. The Editor's Picks / For You tabs are visual only
+// for now; switching their data is a later increment.
+
+import { Theme } from "../foundation/semantic-colors.slint";
+import { Typography } from "../foundation/typography.slint";
+import { HomeState } from "../state.slint";
+import { SectionRow } from "SectionRow.slint";
+import { ScrollView } from "std-widgets.slint";
+
+component Tab inherits Rectangle {
+    in property <string> label;
+    in property <bool> active: false;
+    callback clicked();
+
+    border-radius: 4px;
+    background: root.active ? Theme.surface-main
+        : ta.has-hover ? Theme.surface-hover : transparent;
+
+    HorizontalLayout {
+        padding-left: 14px;
+        padding-right: 14px;
+        padding-top: 6px;
+        padding-bottom: 6px;
+        Text {
+            text: root.label;
+            color: root.active ? Theme.text-primary : Theme.text-muted;
+            font-size: 13px;
+            font-weight: Typography.medium;
+        }
+    }
+
+    ta := TouchArea {
+        mouse-cursor: pointer;
+        clicked => {
+            root.clicked();
+        }
+    }
+}
+
+export component HomeView inherits Rectangle {
+    background: Theme.surface-main;
+
+    ScrollView {
+        VerticalLayout {
+            padding: 32px;
+            spacing: 28px;
+            alignment: start;
+
+            Text {
+                text: HomeState.greeting;
+                visible: HomeState.greeting != "";
+                color: Theme.text-primary;
+                font-size: 26px;
+                font-weight: Typography.semibold;
+            }
+
+            HorizontalLayout {
+                alignment: start;
+                Rectangle {
+                    background: Theme.surface-elevated;
+                    border-radius: 6px;
+                    HorizontalLayout {
+                        padding: 3px;
+                        spacing: 4px;
+                        Tab { label: @tr("Home"); active: true; }
+                        Tab { label: @tr("Editor's Picks"); }
+                        Tab { label: @tr("For You"); }
+                    }
+                }
+            }
+
+            if HomeState.loading && HomeState.sections.length == 0: Text {
+                text: @tr("Loading your music...");
+                color: Theme.text-muted;
+                font-size: 14px;
+            }
+
+            for section in HomeState.sections: SectionRow {
+                section: section;
+            }
+        }
+    }
+}

crates/qbz-slint/ui/discover/SectionRow.slint

@@ -0,0 +1,34 @@
+// One Discover section — a title and a horizontally scrollable row of
+// album cards.
+//
+// The Svelte original paginates by slice; the MVP uses a horizontal
+// scroll, which is simpler and behaviorally equivalent for browsing.
+
+import { Theme } from "../foundation/semantic-colors.slint";
+import { Typography } from "../foundation/typography.slint";
+import { DiscoverSection } from "../state.slint";
+import { AlbumCard } from "AlbumCard.slint";
+import { ScrollView } from "std-widgets.slint";
+
+export component SectionRow inherits VerticalLayout {
+    in property <DiscoverSection> section;
+
+    spacing: 12px;
+
+    Text {
+        text: root.section.title;
+        color: Theme.text-primary;
+        font-size: 18px;
+        font-weight: Typography.semibold;
+    }
+
+    ScrollView {
+        height: 290px;
+        HorizontalLayout {
+            spacing: 32px;
+            for album in root.section.albums: AlbumCard {
+                album: album;
+            }
+        }
+    }
+}

crates/qbz-slint/ui/shell/AppShell.slint

@@ -6,11 +6,10 @@
 
 import { Theme } from "../foundation/semantic-colors.slint";
 import { Layout } from "../foundation/layout.slint";
-import { Spacing } from "../foundation/spacing.slint";
-import { Typography } from "../foundation/typography.slint";
 import { Sidebar } from "Sidebar.slint";
 import { HeaderBar } from "HeaderBar.slint";
 import { PlayerBar } from "PlayerBar.slint";
+import { HomeView } from "../discover/HomeView.slint";
 
 export component AppShell inherits Rectangle {
     background: Theme.surface-main;
@@ -29,34 +28,12 @@ export component AppShell inherits Rectangle {
             spacing: 0px;
 
             Sidebar { }
-
-            // Content region — placeholder until the Discover/Home view.
             Rectangle {
+                width: Layout.hairline;
+                background: Theme.border-subtle;
+            }
+            HomeView {
                 horizontal-stretch: 1;
-                background: Theme.surface-main;
-
-                VerticalLayout {
-                    alignment: center;
-                    HorizontalLayout {
-                        alignment: center;
-                        VerticalLayout {
-                            spacing: Spacing.sm;
-                            Text {
-                                text: "Discover — Home";
-                                color: Theme.text-primary;
-                                font-size: 22px;
-                                font-weight: Typography.semibold;
-                                horizontal-alignment: center;
-                            }
-                            Text {
-                                text: "Content view lands in the next increment";
-                                color: Theme.text-muted;
-                                font-size: Typography.body;
-                                horizontal-alignment: center;
-                            }
-                        }
-                    }
-                }
             }
         }
 

crates/qbz-slint/ui/state.slint

@@ -0,0 +1,26 @@
+// Shared UI state — structs and globals the Rust controllers populate.
+//
+// The Rust side builds these models on a worker thread, then sets them
+// on the global from the Slint event loop (see src/home.rs, src/main.rs).
+
+export struct AlbumCardItem {
+    id: string,
+    title: string,
+    artist: string,
+    quality: string,
+    ribbon: string,
+    ribbon-kind: string,   // "press" | "qobuzissime" | "albumOfTheWeek" | ""
+    artwork-url: string,
+}
+
+export struct DiscoverSection {
+    title: string,
+    albums: [AlbumCardItem],
+}
+
+// Discover / Home screen state.
+export global HomeState {
+    in property <string> greeting: "";
+    in property <[DiscoverSection]> sections: [];
+    in property <bool> loading: false;
+}