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

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

apps/api/utils/courses/archive.util.js

@@ -0,0 +1,31 @@
+"use strict";
+
+/**
+ * Single archive — soft delete one record
+ */
+async function archiveOne(Model, where, deletedBy, transaction) {
+  const record = await Model.findOne({ where, transaction });
+  if (!record) return null;
+  await record.update({ deletedBy: deletedBy ?? null }, { transaction });
+  await record.destroy({ transaction });
+  return record;
+}
+
+/**
+ * Bulk archive — soft delete multiple records by primary key
+ */
+async function archiveMany(Model, pkField, ids, deletedBy, transaction) {
+  if (!ids?.length) return 0;
+
+  const records = await Model.findAll({ where: { [pkField]: ids, deletedAt: null } });
+  if (!records.length) return 0;
+
+  for (const record of records) {
+    await record.update({ deletedBy: deletedBy ?? null }, { transaction });
+    await record.destroy({ transaction });
+  }
+
+  return records.length;
+}
+
+module.exports = { archiveOne, archiveMany };