switch to launch builder instead of macro for fullstack

packages/fullstack/src/adapters/salvo_adapter.rs

@@ -375,10 +375,18 @@ async fn convert_response(response: HyperResponse, res: &mut Response) {
     }
 }
 
-struct SSRHandler<P: Clone> {
+/// A handler that renders a Dioxus application to HTML using server-side rendering.
+pub struct SSRHandler<P: Clone> {
     cfg: ServeConfig<P>,
 }
 
+impl<P: Clone> SSRHandler<P> {
+    /// Creates a new SSR handler with the given configuration.
+    pub fn new(cfg: ServeConfig<P>) -> Self {
+        Self { cfg }
+    }
+}
+
 #[async_trait]
 impl<P: Clone + serde::Serialize + Send + Sync + 'static> Handler for SSRHandler<P> {
     async fn handle(