fix(events): point Messaging settings at suite defaults, not API keys

Mirror Care: suite platform keys count as ready for attendee email/SMS;
Account Messaging is primary, product Bird/SMS keys are advanced.
SmsService now prefers channel=suite before customer API keys.

app/Services/Events/EventSpeakerInviteService.php

@@ -227,7 +227,7 @@ class EventSpeakerInviteService
         }
 
         if (! app(EventMailer::class)->isConfiguredForOwner($ownerRef)) {
-            return ['ok' => false, 'error' => 'Connect Ladill Bird in Integrations before sending speaker invitations.'];
+            return ['ok' => false, 'error' => 'Email is not available yet. Bind a mailbox under Account → Messaging once platform keys are configured, or connect Bird under Advanced keys.'];
         }
 
         $token = (string) ($speaker['invite_token'] ?? '');