refactor: repartition server-side and client-side code

app/.client/persistence/local-storage.ts

@@ -0,0 +1,28 @@
+// Client-side storage utilities
+const isClient = typeof window !== 'undefined' && typeof localStorage !== 'undefined';
+
+export function getLocalStorage(key: string): any | null {
+  if (!isClient) {
+    return null;
+  }
+
+  try {
+    const item = localStorage.getItem(key);
+    return item ? JSON.parse(item) : null;
+  } catch (error) {
+    console.error(`Error reading from localStorage key "${key}":`, error);
+    return null;
+  }
+}
+
+export function setLocalStorage(key: string, value: any): void {
+  if (!isClient) {
+    return;
+  }
+
+  try {
+    localStorage.setItem(key, JSON.stringify(value));
+  } catch (error) {
+    console.error(`Error writing to localStorage key "${key}":`, error);
+  }
+}