List Allocation Models

Retrieve the list of allocation model portfolios available under the authenticated Financial Advisor account. Each response entry is keyed by the model name and its value is a delimited string containing the master account identifier, model name, and internal model designator/flag tokens separated by the `\x1d` (ASCII group separator) character. **IMPORTANT:** Ensure this endpoint is queried **first**, prior to accessing any other Model Portfolio resources in the Web API. The model list returned here primes the session's model context and is required before subsequent Model Portfolio endpoints (model summary, positions, invest/divest, rebalance, order submission, etc.) will return correct results.