Adaptive CI/CD Workflow Orchestrator

Design a system to manage complex software build pipelines. Users define 'Workflows' consisting of 'Stages' and 'Tasks'. Tasks can be shell scripts, docker commands, or notification triggers. Tasks within a stage may run in parallel or sequence based on dependencies. The system must support automatic rollbacks (undoing successful tasks in reverse order) if a mandatory task fails, and real-time progress monitoring for a dashboard.