[feat] add website update button to about dialog

apps/desktop/src/gui/application/gui_application.cpp

@@ -1740,6 +1740,7 @@ void GuiApplication::BindMainCallbacks(bool gallery_window) {
     OpenUrl(latest && !latest->download_url.empty() ? latest->download_url
                                                    : "https://crossdesk.cn");
   });
+  main->on_open_website([this] { OpenUrl("https://crossdesk.cn"); });
   main->on_open_afdian_sponsor([this] {
     OpenUrl("https://afdian.com/a/kunkundi");
   });

apps/desktop/src/gui/ui/main_window.slint

@@ -492,6 +492,7 @@ export component MainWindow inherits Window {
     callback cancel-self-hosted-settings;
     callback browse-save-path;
     callback open-download;
+    callback open-website;
     callback open-afdian-sponsor;
     callback open-github-sponsor;
     callback open-kofi-sponsor;
@@ -2446,6 +2447,15 @@ export component MainWindow inherits Window {
                         font-size: 12px; wrap: word-wrap; overflow: elide;
                         vertical-alignment: center;
                     }
+                    if root.update-available: WorkbenchButton {
+                        width: max(80px, about-update-button-metrics.preferred-width + 24px);
+                        height: 32px;
+                        primary: true;
+                        text-size: 12px;
+                        text: UiStrings.download;
+                        clicked => { root.open-website(); }
+                        about-update-button-metrics := Text { visible: false; text: UiStrings.download; font-size: 12px; }
+                    }
                     SettingsButton {
                         width: max(116px, check-button-metrics.preferred-width + 24px);
                         text: UiStrings.check-for-updates;