enhancement: add complete JSDoc comments to all SDK functions

[devmocrea]

Description

To improve third-party developer adoption, document all exported functions in the SDK using comprehensive TypeScript JSDoc comments.

Technical Specification

• Add structured JSDoc headers to:
  • callCreateCircle
  • callContribute
  • callTriggerPayout
• Document all parameters, return parameters, and thrown errors.

Acceptance Criteria

• Developers see rich, structured tooltips and autocomplete information in their IDEs when using the SDK.