Hide the desktop window's title bar and default menu

Extract desktop window setup into its own crates/web/src/desktop.rs
module (SRP) with a single config() function, wired into main.rs via
LaunchBuilder::desktop().with_cfg(...). Disabling window decorations
also clears dioxus-desktop's default native menu bar as a side effect,
since it exists to give a decorated window something to hang off of.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

crates/web/src/desktop.rs

@@ -0,0 +1,12 @@
+use dioxus::desktop::{Config, WindowBuilder};
+
+/// Desktop window configuration: a borderless window with no OS title bar.
+///
+/// Dropping decorations also drops dioxus-desktop's default native menu bar
+/// (Window/Edit/Help) — the crate only keeps that menu around to give a
+/// decorated window something to hang it off of, and clears it automatically
+/// once `with_decorations(false)` is set, so there's nothing further to do
+/// here to get rid of it.
+pub fn config() -> Config {
+    Config::new().with_window(WindowBuilder::new().with_decorations(false))
+}

crates/web/src/main.rs

@@ -1,6 +1,9 @@
 mod api;
 mod app;
 
+#[cfg(feature = "desktop")]
+mod desktop;
+
 #[cfg(feature = "server")]
 mod server;
 
@@ -14,7 +17,9 @@ fn main() {
     // `#[server]` calls) — it would stand up an axum server instead of a
     // window. Pick the desktop renderer explicitly in that case.
     #[cfg(feature = "desktop")]
-    dioxus::LaunchBuilder::desktop().launch(app::App);
+    dioxus::LaunchBuilder::desktop()
+        .with_cfg(desktop::config())
+        .launch(app::App);
 
     #[cfg(not(feature = "desktop"))]
     dioxus::launch(app::App);