[Work Item] Add JSDoc comments to CSAPI methods

[Sam-Bolling]

📌 Task Description

Add JSDoc comments to all CSAPI methods implemented in ConnectedSystemsClient. Each method should include clear documentation for parameters, return types, and usage context.

This ensures consistency with upstream TypeScript standards and improves developer experience for contributors and downstream users.

✅ Acceptance Criteria

• JSDoc comments added to all CSAPI methods
• Includes parameter descriptions and return types
• Follows formatting conventions used in upstream repo
• Improves IDE support and contributor clarity
• Linked to GitHub Project board

🔗 Related Links

• Test Suite Issue
• Implementation Plan