feat: show favicon in fetch output

[cursor]

Summary

• The public JS SDK fetch response and fetch task output require a favicon URL, but the CLI's human-readable formatter omitted it.
• Show the favicon URL for synchronous fetches and completed fetch tasks.
• Add unit and integration coverage and update the README.

Validation

• npm run build
• npm run lint
• npm test (23 files, 179 tests passed)

  

[Turanic]

The response already support additional response fields with json output, so this change is not required per say. No need to add it to the "human readable output".