frontend: add color theme & theme switcher

frontend/app/store/theme-store.js

@@ -0,0 +1,20 @@
+"use client";
+import { create } from "zustand";
+
+export function setTheme(theme) {
+  localStorage.setItem("theme", theme);
+}
+export function getTheme() {
+  return localStorage.getItem("theme");
+}
+
+export const useThemeStore = create((set) => ({
+  theme: "light",
+  changeTheme: (theme) => {
+    set({ theme: theme });
+    setTheme(theme);
+  },
+  checkTheme: () => {
+    set({ theme: getTheme() || "light" });
+  }
+}));