Agent authority description
- **Level 1 agent**: can manage level 2 and level 3 agents, can manage users
- **Level 2 agent**: can manage level 3 agents, can manage users
- **Level 3 agent**: can only manage users
Agent relationship maintenance
- **Automatic maintenance**: the system automatically maintains the agent hierarchy relationship
- **Relationship verification**: verify the legitimacy of the agent relationship when creating it
- **Relationship adjustment**: support agent relationship adjustment