Add per-customer SMS and Bird Integrations for event messaging.

Attendee and speaker comms use encrypted tenant relay credentials and skip platform-key fallback and Bird wallet double-debit.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Http/Controllers/Events/AttendeeController.php

@@ -182,8 +182,8 @@ class AttendeeController extends Controller
         ]);
 
         $preview = $this->comms->preview($event, $validated['mode']);
-        if (! $preview['affordable']) {
-            return back()->with('error', 'Insufficient wallet balance. Add funds in Billing before sending.');
+        if ($preview['integrations_error'] ?? null) {
+            return back()->with('error', $preview['integrations_error']);
         }
 
         if ($preview['recipients'] === 0) {