Endpoints Principales
GET /health - Health check
GET /sessions - Listar sesiones
POST /sessions - Crear sesiĆ³n
GET /sessions/:id/qr - Obtener QR
GET /sessions/:id/status - Estado sesiĆ³n
DELETE /sessions/:id - Eliminar sesiĆ³n
POST /sessions/:id/messages/text - Enviar texto
POST /sessions/:id/messages/media - Enviar media