feat: configure Payload SMTP email adapter

lib/email/payloadAdapter.ts

@@ -0,0 +1,15 @@
+import type { PayloadEmailAdapter } from "payload";
+import { getMailFrom, getMailTransport } from "./transport";
+
+/** Connects Payload's built-in auth emails to the same SMTP transport as ANOUMA's own emails. */
+export const payloadEmailAdapter: PayloadEmailAdapter = () => ({
+  name: "anouma-smtp",
+  defaultFromAddress: process.env.SMTP_USER || "support@anouma.org",
+  defaultFromName: "ANOUMA",
+  sendEmail: async (message) => {
+    return getMailTransport().sendMail({
+      ...message,
+      from: message.from || getMailFrom(),
+    });
+  },
+});