👥 System Admin - Agent Management

POST Payload Parameters:

{
  "username": "string (required)",
  "email": "string (required)",
  "password": "string (required)",
  "agent_type": "string (required) - 'shareholder', 't1', or 't2'",
  "upline_by": "string (optional) - User ID of upline (required for t1/t2)",
  "first_name": "string (required)",
  "last_name": "string (required)",
  "phone": "string (optional)",
  "wallet_address": "string (optional)"
}

Notes:
- Shareholder: upline_by not required
- T1 agent: upline_by must be a shareholder user ID
- T2 agent: upline_by must be a T1 agent user ID