docs: add JSDoc headers to all externally exported store functions

src/store/companyuser/getByEmail.js

@@ -1,5 +1,16 @@
 import { GET_BY_EMAIL } from '../../sql/companyuser.js';
 
+/**
+ * Returns the company user ids associated with the given email address.
+ *
+ * @param {object} pool - The mssql connection pool.
+ * @returns {Function} An async function that resolves the company user ids for an email.
+ *
+ * @example
+ * const fn = getByEmail(pool);
+ * const ids = await fn('user@example.com');
+ * // => [1, 2, 3]
+ */
 export default function getByEmail(pool) {
   return async (email) => {
     const result = await pool