fix: drop the duplicate envelope from the empty article pane

src/view.rs

@@ -416,8 +416,9 @@ impl CarrierWidgets {
         actions.add_css_class("toolbar");
         article.append(&actions);
 
+        // No icon: the pane sits directly under the list's own empty page,
+        // and two envelopes stacked up the window say nothing twice.
         let article_empty = adw::StatusPage::builder()
-            .icon_name("mail-read-symbolic")
             .title("No message selected")
             .description("Pick a message from the list above to read it.")
             .build();