frontend: add saving of settings state. move logout button in navigation. add close button to settings dialog.

frontend/app/store/settings-store.js

@@ -0,0 +1,25 @@
+"use client";
+import { create } from "zustand";
+import { persist, createJSONStorage } from "zustand/middleware";
+
+function saveSettings(dict) {
+  localStorage.setItem("settings", JSON.stringify(dict));
+}
+
+function loadSettings() {
+  return JSON.parse(localStorage.getItem("settings"));
+}
+
+export const useSettingsStore = create(
+  persist(
+    (set, get) => ({
+      saveToHistory: true,
+      setSettings: (dict) => {
+        set(dict);
+      },
+    }),
+    {
+      name: "settings",
+    },
+  ),
+);