docs: add JSDoc headers to all externally exported store functions

src/store/posterminal/setOn.js

@@ -1,6 +1,17 @@
 import { GET_BY_ID, SET_ON, LIST_CATEGORY_IDS } from '../../sql/posterminal.js';
 import resolveCompanyAccess from '../companyuser/resolveCompanyAccess.js';
 
+/**
+ * Assigns a category to a posterminal (turns it on for that category).
+ *
+ * @param {object} pool - The mssql connection pool.
+ * @returns {Function} An async function that assigns a category to a posterminal.
+ *
+ * @example
+ * const fn = setOn(pool);
+ * const result = await fn(42, 1, 5, 9);
+ * // => { id, categoryIds: [9, ...] }
+ */
 export default function setOn(pool) {
   const access = resolveCompanyAccess(pool);