Implemented ConfigDrivenWorkflowEngine in workflow_v2.py: Created src/trckr_plow/workflow_v2.py with a standalone ConfigDrivenWorkflowEngine class. The class loads WorkflowConfig on initialization (accepts pre-loaded config or loads from path). Maintains the same interface as WorkflowEngine for drop-in replacement. All 350 tests pass, including 34 new tests for the workflow_v2 module.