Task: Implement WorkflowService with ListWorkflowsAsync

[charleslbryant]

Part of Issue #22 - Workflow List Command

Summary

Implement the concrete WorkflowService class with list workflows functionality

Acceptance Criteria

• Create WorkflowService implementation in Services/WorkflowManagement/
• Implement ListWorkflowsAsync using N8nWorkflowClient
• Include proper error handling and logging
• Follow existing service implementation patterns
• Include dependency injection support

Parent Issues

• Resolves part of CRD-2.1: Workflow List Command #22
• Depends on Task: Create IWorkflowService interface with ListWorkflowsAsync method #31, Task: Create N8nWorkflowClient infrastructure for workflow API calls #32