#18: implement SMTP Submission (587/465), SASL PLAIN/LOGIN auth and preflight diagnostics

services/protocols/internal/application/port/auth_repository.go

@@ -6,10 +6,15 @@ import (
 	"github.com/google/uuid"
 )
 
-// MailboxAuth is the subset of mailbox data needed to verify a login.
+// MailboxAuth is the subset of mailbox data needed to verify a login and,
+// once authenticated, to apply the sender policy of PLAN.md section 5.2.
 type MailboxAuth struct {
 	ID           uuid.UUID
 	PasswordHash string
+	EmailAddress string
+	DomainName   string
+	// MaxRecipientsPerHour caps a compromised account's blast radius.
+	MaxRecipientsPerHour int
 }
 
 // AuthRepository resolves a login address to its stored credential.