get https://example.com/api/v1/balance/agent/
Get the total balance for an agent, converted to USD. If the agent has multiple asset accounts, returns the sum of all balances in USD.
Args: session: Database session agent_id: The ID of the agent api_key: API key for authentication secret: API secret for authentication request: FastAPI request object for rate limiting
Returns: AgentBalanceResponse: The total balance in USD and breakdown by asset