refactor: remove embedded wallpaper from binary (v0.5.2)

Wallpaper is installed by moonarch to /usr/share/moonarch/wallpaper.jpg.
Embedding a 374K JPEG in the binary was redundant. Without a wallpaper
file, GTK background color (Catppuccin Mocha base) shows through and
wallpaper-only windows on secondary monitors are skipped.

src/main.rs

@@ -51,15 +51,11 @@ fn activate(app: &gtk::Application) {
 
     // Load config and resolve wallpaper
     let config = config::load_config(None);
-    let bg_path = config::resolve_background_path(&config);
-    log::debug!("Background path: {}", bg_path.display());
-
-    // Load background texture once — shared across all windows
-    // Blur is applied on the GPU via GskBlurNode at widget realization time.
-    let bg_texture = greeter::load_background_texture(&bg_path);
-    if bg_texture.is_none() {
-        log::error!("Failed to load background texture — greeter will start without wallpaper");
-    }
+    let bg_texture = config::resolve_background_path(&config)
+        .and_then(|path| {
+            log::debug!("Background path: {}", path.display());
+            greeter::load_background_texture(&path)
+        });
 
     let use_layer_shell = std::env::var("MOONGREET_NO_LAYER_SHELL").is_err();
     log::debug!("Layer shell: {use_layer_shell}");