feat: RFQ Workflow

[danielgnh]

This pull request adds full support for the RFQ (Request for Quote) workflow to the codebase, enabling institutional trading features such as negotiated pricing and large order handling. The changes introduce a new Rfq resource with methods for creating, listing, quoting, accepting, approving, and canceling RFQ requests and quotes. Additionally, relevant enums are added to facilitate sorting and filtering, and an example script demonstrates the complete RFQ workflow.

RFQ Workflow Support

• Added the new Rfq resource class with methods for creating, listing, quoting, accepting, approving, and canceling RFQ requests and quotes (src/Resources/Clob/Rfq.php).
• Integrated the rfq() accessor into the Clob class, allowing users to interact with the RFQ resource (src/Clob.php). [1] [2] [3]

Enums for RFQ Operations

• Introduced RfqSortBy, RfqSortDir, and RfqState enums to support sorting, filtering, and state management in RFQ operations (src/Enums/RfqSortBy.php, src/Enums/RfqSortDir.php, src/Enums/RfqState.php). [1] [2] [3]

Documentation and Examples

• Added a comprehensive example script demonstrating the full RFQ workflow, including request creation, quoting, acceptance, approval, and cancellation (examples/rfq-workflow.php).