feat(wallpaper): add apply_wallpaper workflow and rotation worker

Adds a new apply_wallpaper command and its plumbing across
desktop, mobile, and Android. A WorkManager-based rotation
worker handles applying wallpapers in the background. Wallpaper
state now tracks currentId and imageIds for precise control.

- Introduced apply_wallpaper command across desktop, mobile and Android
- Added WorkManager-based rotation worker to apply wallpapers in the
  background
- Extended wallpaper state with currentId and imageIds and updated schemas/permissions

plugins/src/models.rs

@@ -9,6 +9,8 @@ pub struct WallpaperState {
     pub shuffle: bool,
     pub lock_screen_only: bool,
     pub current_index: usize,
+    pub current_id: Option<String>,
+    pub image_ids: Vec<String>,
     pub image_urls: Vec<String>,
 }
 
@@ -38,6 +40,12 @@ pub struct DeleteImageRequest {
     pub id: String,
 }
 
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ApplyWallpaperRequest {
+    pub id: String,
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct DeleteImagesRequest {