chore: relocate backend into apps/api ahead of monorepo merge

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/api/utils/notificationVisibility.util.js

@@ -0,0 +1,25 @@
+/***********************************************************************************************************************************************************************
+ * File Name    : notificationVisibility.util.js
+ * Type         : Utility
+ * Description  : Shared visibility-window filter for AdminNotification/
+ *                UserNotification rows carrying a denormalized start_date/
+ *                end_date (copied from NotificationBroadcast at send time —
+ *                see notificationBroadcasts.controller.js#sendBroadcast).
+ *                Non-announcement notifications have both columns null, so
+ *                this filter is a no-op for them.
+ *
+ * Author: Kenneth Obsequio (@lash0000)
+ * Date Created: Jul. 11, 2026
+ ***********************************************************************************************************************************************************************/
+const { Op } = require('sequelize');
+
+function notInFutureOrExpired(now = new Date()) {
+  return {
+    [Op.and]: [
+      { [Op.or]: [{ start_date: null }, { start_date: { [Op.lte]: now } }] },
+      { [Op.or]: [{ end_date: null }, { end_date: { [Op.gte]: now } }] },
+    ],
+  };
+}
+
+module.exports = { notInFutureOrExpired };