Implements marking conversations as read when clicked on

src/application/main-window.vala

@@ -45,6 +45,7 @@ public class MainWindow : Adw.ApplicationWindow
                 transcript_view.title = conversation.display_name;
                 
                 try {
+                    Repository.get_instance().mark_conversation_as_read(conversation.guid);
                     Repository.get_instance().sync_conversation(conversation.guid);
                 } catch (Error e) {
                     GLib.warning("Failed to sync conversation: %s", e.message);