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/overlay.rs

@@ -0,0 +1,62 @@
+//! This example demonstrates how to create an overlay window with dioxus.
+//!
+//! Basically, we just create a new window with a transparent background and no decorations, size it to the screen, and
+//! then we can draw whatever we want on it. In this case, we're drawing a simple overlay with a draggable header.
+//!
+//! We also add a global shortcut to toggle the overlay on and off, so you could build a raycast-type app with this.
+
+use dioxus::desktop::{
+    HotKeyState, LogicalSize, WindowBuilder, tao::dpi::PhysicalPosition, use_global_shortcut,
+};
+use dioxus::prelude::*;
+
+fn main() {
+    dioxus::LaunchBuilder::desktop()
+        .with_cfg(make_config())
+        .launch(app);
+}
+
+fn app() -> Element {
+    let mut show_overlay = use_signal(|| true);
+
+    _ = use_global_shortcut("cmd+g", move |state| {
+        if state == HotKeyState::Pressed {
+            show_overlay.toggle();
+        }
+    });
+
+    rsx! {
+        Stylesheet { href: asset!("/examples/assets/overlay.css") }
+        if show_overlay() {
+            div {
+                width: "100%",
+                height: "100%",
+                background_color: "red",
+                border: "1px solid black",
+
+                div {
+                    width: "100%",
+                    height: "10px",
+                    background_color: "black",
+                    onmousedown: move |_| dioxus::desktop::window().drag(),
+                }
+
+                "This is an overlay!"
+            }
+        }
+    }
+}
+
+fn make_config() -> dioxus::desktop::Config {
+    dioxus::desktop::Config::default().with_window(make_window())
+}
+
+fn make_window() -> WindowBuilder {
+    WindowBuilder::new()
+        .with_transparent(true)
+        .with_decorations(false)
+        .with_resizable(false)
+        .with_always_on_top(true)
+        .with_position(PhysicalPosition::new(0, 0))
+        .with_max_inner_size(LogicalSize::new(100000, 50))
+}