Summary

When I debug an A2A server I want to ensure it works as expected when I download artifacts. Some A2A servers provide artifacts, some don't.

The above mention command should download all the artifacts created by a specific task.

There should be an option to pass it also a flag for --artifact-id which then would only download that particular artifact id items.

Artifacts are downloaded using the ADK client utility for downloading artifacts.

Those would be downloaded to a given directory using the --output flag or short for -o. Defaulting to ./downloads directory.

Example Code:
https://raw.githubusercontent.com/inference-gateway/adk/refs/heads/main/examples/artifacts-with-default-handlers/client/main.go

Acceptance Criteria

• There is a new command a2a artifacts download --task-id <task_id> --artifact-id <artifact_id>
• The command is downloading all artifacts of a task if no artifact id is specified
• The command is using the A2A ADK CLI artifacts helper utility mentioned above in the example
• The command is documented
• It's tested