cmd error parsing: show a "try again after" message when a response sets a Retry-After header

[IsaacG]

No description provided.

[Copilot]

Pull Request Overview

This PR updates error response handling to display a "try again after" message when an API returns a Retry-After header, and refines test helpers for different error status codes.

• Renames the existing error response helper to errorResponse418 for 418 errors.
• Adds a new error response helper errorResponse429 for 429 responses with a Retry-After header.
• Updates decodedAPIError to check for and appropriately format the Retry-After header in error messages.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
cmd/cmd_test.go	Updated helper functions and tests to simulate 418 and 429 responses.
cmd/cmd.go	Added logic in decodedAPIError to format Retry-After values in errors.

Comments suppressed due to low confidence (1)

cmd/cmd.go:85

• Consider adding a brief comment here clarifying that if the Retry-After header cannot be parsed as an integer, its value is assumed to be a pre-formatted HTTP date.

	if retryAfter := resp.Header.Get("Retry-After"); retryAfter != "" {

[iHiD]

Looks good to me. Thank you. I'd like another pair of eyes before merging though

[ErikSchierboom]

LGTM