feat: WhatsApp Nucleo con Nuxt 4 + Baileys v7

Reemplazo completo de Evolution API por implementación directa con Baileys.

Características:
- Dashboard completo con Nuxt UI v4
- Soporte para múltiples instancias de WhatsApp
- Conexión via QR code o pairing code
- Persistencia de mensajes en PostgreSQL
- API REST para integraciones externas
- Webhooks con firma HMAC
- SSE para actualizaciones en tiempo real
- Autenticación con Authentik

server/api/instances/[id]/pairing-code.post.ts

@@ -0,0 +1,69 @@
+/**
+ * POST /api/instances/:id/pairing-code
+ * Request a pairing code for connection without QR
+ */
+import { query } from '../../../utils/database'
+import { baileysManager } from '../../../services/baileys/manager'
+
+interface PairingCodeBody {
+  phoneNumber: string
+}
+
+export default defineEventHandler(async (event) => {
+  const username = getHeader(event, 'x-authentik-username')
+  if (!username) {
+    throw createError({ statusCode: 401, message: 'Unauthorized' })
+  }
+
+  const id = getRouterParam(event, 'id')
+  const body = await readBody<PairingCodeBody>(event)
+
+  if (!body.phoneNumber?.trim()) {
+    throw createError({ statusCode: 400, message: 'Phone number is required' })
+  }
+
+  // Clean phone number (remove +, spaces, dashes)
+  const cleanPhone = body.phoneNumber.replace(/[^0-9]/g, '')
+
+  // Check if instance exists
+  const result = await query<{ id: string; status: string }>(
+    'SELECT id, status FROM instances WHERE id = $1',
+    [id]
+  )
+
+  if (result.rows.length === 0) {
+    throw createError({ statusCode: 404, message: 'Instance not found' })
+  }
+
+  const instance = result.rows[0]
+
+  if (instance.status === 'connected') {
+    throw createError({ statusCode: 400, message: 'Instance already connected' })
+  }
+
+  try {
+    // Connect with pairing code mode
+    await baileysManager.connect(id!, true, cleanPhone)
+
+    // Wait for pairing code
+    await new Promise(resolve => setTimeout(resolve, 5000))
+
+    const pairingCode = baileysManager.getPairingCode(id!)
+    const status = baileysManager.getStatus(id!)
+
+    if (!pairingCode) {
+      throw new Error('Failed to generate pairing code')
+    }
+
+    return {
+      success: true,
+      code: pairingCode,
+      status: status?.status || 'pairing'
+    }
+  } catch (error) {
+    throw createError({
+      statusCode: 500,
+      message: `Failed to request pairing code: ${(error as Error).message}`
+    })
+  }
+})