fix: Info.query_order_by_oid returns unknownOid sometimes

[domiclaw]

Summary

This PR fixes issue #253 where Info.query_order_by_oid was returning "unknownOid" when querying orders on non-default DEXes. The root cause was that the method was missing the dex parameter that other order-related methods (open_orders, etc.) support.

Changes

• Added dex: str = "" parameter to Info.query_order_by_oid() method
• Added dex: str = "" parameter to Info.query_order_by_cloid() method for consistency
• Updated both methods to pass the dex parameter in the API request body
• Added comprehensive docstrings documenting the new parameter

Testing

• Existing tests pass where network requests are mocked
• The fix maintains backward compatibility (default dex="")
• When querying orders fetched via open_orders(dex="..."), you must now pass the same dex value to query_order_by_oid() to locate the order

Fixes #253