Clean up shared UI runtime state

src/desktop/platform.rs

@@ -0,0 +1,22 @@
+use crate::platform::OpenUrl;
+use crate::prelude::HasDesktopUiState;
+
+impl<T: HasDesktopUiState> OpenUrl for T {
+    fn open_url(&mut self, url: &str) {
+        let (program, first): (&str, &[&str]) = if cfg!(target_os = "macos") {
+            ("open", &[])
+        } else if cfg!(target_os = "windows") {
+            ("cmd", &["/C", "start", ""])
+        } else {
+            ("xdg-open", &[])
+        };
+        match std::process::Command::new(program)
+            .args(first)
+            .arg(url)
+            .spawn()
+        {
+            Ok(_) => {}
+            Err(e) => log::warn!("could not open {url} with {program}: {e}"),
+        }
+    }
+}