add event listener to hot reload theme

Author: Jappie3

src/App.svelte

@@ -24,6 +24,13 @@
 
   const activeRouteStore = router.activeRouteStore;
 
+  window
+    .matchMedia("(prefers-color-scheme: dark)")
+    .addEventListener("change", ({ matches }) => {
+      theme.set(matches ? "dark" : "light");
+      followSystemTheme.set(true);
+    });
+
   void router.loadFromLocation();
 
   $: document.documentElement.setAttribute("data-codefont", $codeFont);

src/App/Settings.svelte

@@ -11,6 +11,7 @@
   import Button from "@app/components/Button.svelte";
   import Icon from "@app/components/Icon.svelte";
   import Radio from "@app/components/Radio.svelte";
+
 </script>
 
 <style>