peerStore loading order caused issues. Fixed in GameScene (+ extracted a few stores in their files)

front/src/Stores/VisibilityStore.ts

@@ -0,0 +1,16 @@
+import {readable} from "svelte/store";
+
+/**
+ * A store containing whether the current page is visible or not.
+ */
+export const visibilityStore = readable(document.visibilityState === 'visible', function start(set) {
+    const onVisibilityChange = () => {
+        set(document.visibilityState === 'visible');
+    };
+
+    document.addEventListener('visibilitychange', onVisibilityChange);
+
+    return function stop() {
+        document.removeEventListener('visibilitychange', onVisibilityChange);
+    };
+});