fix(futures): align snapshot, quote, trade, and schedules models with OpenAPI spec

[justinpolygon]

Fixes SPT-1694. ## Summary

Aligns the futures client models and method signatures with the formal OpenAPI spec.

• FuturesSnapshot / FuturesSnapshotDetails

  • Added ticker and product_code fields to FuturesSnapshotDetails (these exist in the schema under details, not just at the top level).
  • Updated FuturesSnapshot.from_dict to read ticker/product_code from either the top level or inside details for backward compatibility.

• FuturesQuote and FuturesTrade

  • Added the missing channel field (present in the spec response schema and marked as required in some cases).

• list_futures_schedules

• Removed the session_end_date_any_of parameter (it was not defined in the OpenAPI spec for this endpoint).