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/multiwindow_with_tray_icon.rs

@@ -0,0 +1,45 @@
+//! Multiwindow with tray icon example
+//!
+//! This example shows how to implement a simple multiwindow application and tray icon using dioxus.
+//! This works by spawning a new window when the user clicks a button. We have to build a new virtualdom which has its
+//! own context, root elements, etc.
+//!
+//! This is useful for apps that incorporate settings panels or persistent windows like Raycast.
+
+use dioxus::desktop::{
+    WindowCloseBehaviour,
+    trayicon::{default_tray_icon, init_tray_icon},
+    window,
+};
+use dioxus::prelude::*;
+
+fn main() {
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    use_hook(|| {
+        // Set the close behavior for the main window
+        // This will hide the window instead of closing it when the user clicks the close button
+        window().set_close_behavior(WindowCloseBehaviour::WindowHides);
+
+        // Initialize the tray icon with a default icon and no menu
+        // This will provide the tray into context for the application
+        init_tray_icon(default_tray_icon(), None)
+    });
+
+    rsx! {
+        button {
+            onclick: move |_| {
+                window().new_window(VirtualDom::new(popup), Default::default());
+            },
+            "New Window"
+        }
+    }
+}
+
+fn popup() -> Element {
+    rsx! {
+        div { "This is a popup window!" }
+    }
+}