feat(ADM-018): completed feature

project/migrations/018_notifications.js

@@ -0,0 +1,26 @@
+/** Notification messages with idempotent dispatch. */
+
+/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
+export const up = (pgm) => {
+  pgm.sql(`
+    CREATE TABLE notifications_messages (
+      id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+      event_id text NOT NULL UNIQUE,
+      channel text NOT NULL DEFAULT 'email',
+      template text NOT NULL,
+      recipient text NOT NULL,
+      subject text NOT NULL,
+      body text NOT NULL,
+      status text NOT NULL DEFAULT 'sent',
+      created_at timestamptz NOT NULL DEFAULT now(),
+      CONSTRAINT notifications_messages_channel_check CHECK (channel = 'email'),
+      CONSTRAINT notifications_messages_status_check CHECK (status IN ('sent', 'failed', 'queued'))
+    )
+  `);
+  pgm.sql('CREATE INDEX notifications_messages_template_idx ON notifications_messages (template)');
+};
+
+/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
+export const down = (pgm) => {
+  pgm.sql('DROP TABLE IF EXISTS notifications_messages');
+};