codify "platform" into resolution logic, server-fn/fullstack overhaul (#4596)

overhaul dioxus fullstack using a new implementation of server_fn

This PR is a complete rewrite of dioxus fullstack designed to improve compatibility with axum and to fix a number of compilation errors based on feature flag unification plumbing through macros.

examples/08-apis/custom_menu.rs

@@ -0,0 +1,49 @@
+//! This example shows how to use a custom menu bar with Dioxus desktop.
+//! This example is not supported on the mobile or web renderers.
+
+use dioxus::desktop::{muda::*, use_muda_event_handler};
+use dioxus::prelude::*;
+
+fn main() {
+    // Create a menu bar that only contains the edit menu
+    let menu = Menu::new();
+    let edit_menu = Submenu::new("Edit", true);
+
+    edit_menu
+        .append_items(&[
+            &PredefinedMenuItem::undo(None),
+            &PredefinedMenuItem::redo(None),
+            &PredefinedMenuItem::separator(),
+            &PredefinedMenuItem::cut(None),
+            &PredefinedMenuItem::copy(None),
+            &PredefinedMenuItem::paste(None),
+            &PredefinedMenuItem::select_all(None),
+            &MenuItem::with_id("switch-text", "Switch text", true, None),
+        ])
+        .unwrap();
+
+    menu.append(&edit_menu).unwrap();
+
+    // Create a desktop config that overrides the default menu with the custom menu
+    let config = dioxus::desktop::Config::new().with_menu(menu);
+
+    // Launch the app with the custom menu
+    dioxus::LaunchBuilder::new().with_cfg(config).launch(app)
+}
+
+fn app() -> Element {
+    let mut text = use_signal(String::new);
+    // You can use the `use_muda_event_handler` hook to run code when a menu event is triggered.
+    use_muda_event_handler(move |muda_event| {
+        if muda_event.id() == "switch-text" {
+            text.set("Switched to text".to_string());
+        }
+    });
+
+    rsx! {
+        div {
+            h1 { "Custom Menu" }
+            p { "Text: {text}" }
+        }
+    }
+}