Model wallpaper display policies

config/dot/quickshell/config/PreferenceSchema.qml

@@ -747,6 +747,32 @@ Singleton {
             label: "Wallpaper",
             detail: "Shown on every output"
         },
+        {
+            key: "wallpaperMode", type: "enum", def: "single", group: "wallpaper",
+            label: "Wallpaper mode", detail: "Use one image, rotate a collection, or choose per display",
+            options: [
+                { value: "single", label: "Single" },
+                { value: "slideshow", label: "Slideshow" },
+                { value: "per-monitor", label: "Per display" }
+            ]
+        },
+        {
+            key: "wallpaperSlideshowPaths", type: "json", def: ([]), group: "wallpaper", internal: true,
+            label: "Slideshow collection", detail: "Backgrounds selected for rotation"
+        },
+        {
+            key: "wallpaperIntervalMinutes", type: "int", def: 30, min: 5, max: 1440, step: 5,
+            unit: "min", group: "wallpaper", label: "Change background every",
+            detail: "Time between slideshow images"
+        },
+        {
+            key: "wallpaperShuffle", type: "bool", def: true, group: "wallpaper",
+            label: "Shuffle", detail: "Show every selected image before repeating"
+        },
+        {
+            key: "wallpaperPerMonitor", type: "json", def: ({}), group: "wallpaper", internal: true,
+            label: "Per-display backgrounds", detail: "Background assigned to each connected display"
+        },
 
         // ── Lock-screen appearance ─────────────────────────────────────────
         // scripts/panama-lock validates these again before generating a state