Retrieves an installment advancement by its ID. This endpoint provides enhanced response data including:

• Detailed advancement information with status tracking
• Contract-specific configurations for MULTIPLE_CONTRACTS mode
• Enhanced metadata including creation, update, and cancellation timestamps
• Error messages when applicable

The response format differs based on the advancement condition.

• ALL_CONTRACTS: Returns root-level calculator, reschedule settings, and no contracts array.
• MULTIPLE_CONTRACTS: Returns individual contract configurations in the contracts array.

This endpoint includes additional fields like cancelled_at, error_message, status, and contracts.