smtp: add notify_email field; fix admin notification sent to no-reply sender

app/migrations/applied/006_smtp_notify_email.sql

@@ -0,0 +1,4 @@
+-- Migration 006: add notify_email to smtp_settings
+-- notify_email is the address that receives admin notifications (access requests, etc.)
+-- It is separate from from_email (the sender/no-reply address).
+ALTER TABLE smtp_settings ADD COLUMN notify_email TEXT NOT NULL DEFAULT '';