feat: integrate email + subscription into tenant provisioning, FIEL notification

createTenant now: provisions DB, creates admin user with temp password,
creates initial subscription, and sends welcome email.
FIEL upload sends admin notification email.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/src/services/fiel.service.ts

@@ -4,6 +4,7 @@ import { join } from 'path';
 import { prisma } from '../config/database.js';
 import { env } from '../config/env.js';
 import { encryptFielCredentials, encrypt, decryptFielCredentials } from './sat/sat-crypto.service.js';
+import { emailService } from './email/email.service.js';
 import type { FielStatus } from '@horux/shared';
 
 /**
@@ -144,10 +145,22 @@ export async function uploadFiel(
       console.error('[FIEL] Filesystem storage failed (DB storage OK):', fsError);
     }
 
+    // Notify admin that client uploaded FIEL
+    const tenant = await prisma.tenant.findUnique({
+      where: { id: tenantId },
+      select: { nombre: true, rfc: true },
+    });
+    if (tenant) {
+      emailService.sendFielNotification({
+        clienteNombre: tenant.nombre,
+        clienteRfc: tenant.rfc,
+      }).catch(err => console.error('[EMAIL] FIEL notification failed:', err));
+    }
+
     const daysUntilExpiration = Math.ceil(
       (validUntil.getTime() - Date.now()) / (1000 * 60 * 60 * 24)
     );
-    
+
     return {
       success: true,
       message: 'FIEL configurada correctamente',