Description: As a Salesmsg customer, I'd like a sandbox/dev environment so I can test new features and automations without disrupting our live production setup. Right now, testing anything new means disconnecting our live CRM integration, pausing automations, and reconnecting to a test environment until we've confirmed it works. We've rolled out Salesmsg to our sales team (95% adoption) for SMS and pipeline-stage automations. As we plan to roll out Calling next, we need to test it without interrupting day-to-day operations, and confirm conversation assignment and contact ownership work as expected before going live. A secondary environment that connects to our dev/test CRM, separate from production, would let us validate new features safely before rollout.