fix: titlebar does not follow theme in dark mode (#903)

src-tauri/src/lib.rs

@@ -956,6 +956,8 @@ pub fn run() {
             commands::test_proxy_url,
             commands::get_upstream_proxy_status,
             commands::scan_local_proxies,
+            // Window theme control
+            commands::set_window_theme,
         ]);
 
     let app = builder