feat(wallpaper): add separate selection for light & dark mode

Commons/Settings.qml

@@ -413,7 +413,8 @@ Singleton {
       property string wallhavenResolutionHeight: ""
       property string sortOrder: "name" // "name", "name_desc", "date", "date_desc", "random"
       property list<var> favorites: []
-      // Format: [{ "path": "/path/to/wallpaper.jpg", "colorScheme": "...", "darkMode": true, "useWallpaperColors": true, "generationMethod": "tonal-spot" }]
+      // Format: [{ "path": "...", "appearance": "light"|"dark", "colorScheme": "...", "darkMode": bool, "useWallpaperColors": bool, "generationMethod": "...", "paletteColors": [...] }]
+      // Legacy entries omit "appearance" and use darkMode to infer light vs dark slot.
     }
 
     // applauncher

Commons/ShellState.qml

@@ -269,7 +269,7 @@ Singleton {
           barVisible: BarService.isVisible,
           openedPanel: PanelService.openedPanel?.objectName || "",
           lockScreenActive: PanelService.lockScreen?.active || false,
-          wallpapers: WallpaperService.currentWallpapers || {},
+          wallpapers: WallpaperService.getWallpapersEffectiveMap(),
           desktopWidgetsEditMode: DesktopWidgetRegistry.editMode || false,
           // -------------
           display: shellStateData.display || {},