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]/index.get.ts

@@ -0,0 +1,53 @@
+/**
+ * GET /api/instances/:id
+ * Get instance details
+ */
+import { query } from '../../../utils/database'
+import { baileysManager } from '../../../services/baileys/manager'
+
+interface InstanceRow {
+  id: string
+  name: string
+  phone_number: string | null
+  status: string
+  qr_code: string | null
+  pairing_code: string | null
+  last_connected_at: Date | null
+  created_by: string
+  created_at: Date
+}
+
+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 result = await query<InstanceRow>(
+    `SELECT id, name, phone_number, status, qr_code, pairing_code,
+            last_connected_at, created_by, created_at
+     FROM instances WHERE id = $1`,
+    [id]
+  )
+
+  if (result.rows.length === 0) {
+    throw createError({ statusCode: 404, message: 'Instance not found' })
+  }
+
+  const instance = result.rows[0]
+  const liveStatus = baileysManager.getStatus(instance.id)
+
+  return {
+    id: instance.id,
+    name: instance.name,
+    phoneNumber: instance.phone_number,
+    status: liveStatus?.status || instance.status,
+    qrCode: liveStatus?.qrCode || instance.qr_code,
+    pairingCode: liveStatus?.pairingCode || instance.pairing_code,
+    lastConnectedAt: instance.last_connected_at,
+    createdBy: instance.created_by,
+    createdAt: instance.created_at
+  }
+})