web: make everything ssr-compatible

web/src/routes/settings/debug/+page.svelte

@@ -1,16 +1,17 @@
 <script lang="ts">
+    import { onMount } from "svelte";
+    import { goto } from "$app/navigation";
+
     import { device, app } from "$lib/device";
     import { version } from "$lib/version";
     import settings, { storedSettings } from "$lib/state/settings";
-
-    import { goto } from "$app/navigation";
     import { defaultSettingsPage } from "$lib/settings/defaults";
 
-    $: {
+    onMount(() => {
         if (!$settings.advanced.debug) {
             goto(defaultSettingsPage(), { replaceState: true });
         }
-    }
+    });
 </script>
 
 {#if $settings.advanced.debug}