Make user input saving account-specific

public/scripts/user.js

@@ -43,6 +43,14 @@ export function isAdmin() {
     return Boolean(currentUser.admin);
 }
 
+/**
+ * Gets the handle string of the current user.
+ * @returns {string} User handle
+ */
+export function getCurrentUserHandle() {
+    return currentUser?.handle || 'default-user';
+}
+
 /**
  * Get the current user.
  * @returns {Promise<void>}