Add API Endpoints for Managing Individual Agent Flows

We’d like the ability to manage individual flows within an agent via the API, rather than having to submit the entire agent definition when making changes.

Currently, the Edit Agent API requires re-submitting the full agent object, including all flows, even when we only need to modify one. This introduces unnecessary complexity when automating changes at scale.

Would you consider exposing a set of flow-level endpoints, such as:
GET /agents/{agentId}/agentFlows/{agentFlowId}
POST /agents/{agentId}/agentFlows
PATCH /agents/{agentId}/agentFlows/{agentFlowId}
DELETE /agents/{agentId}/agentFlows/{agentFlowId}

Benefits of this enhancement:
- Reduces the risk of unintentionally overwriting unrelated flows during updates
- Simplifies automation logic by allowing more granular control
- Improves traceability and auditability during restores and deployments
- Aligns better with how Host schedules are managed today