Improve error handling in `flags.LatestFlag()`

[digitalghost-dev]

The flags.LatestFlag() function currently always returns nil for errors, even when operations fail (network errors, JSON parsing errors, etc.). This means:

• The CLI always exits with code 0 (success), even on failure
• Callers have no way to distinguish between success and failure
• Error messages are printed, but the program reports success

Solution

Refactor flags.LatestRelease() to return errors properly:

1. Change function signature: func latestRelease(output *strings.Builder) error
2. Return actual errors for all failure cases (URL parsing, HTTP requests, JSON unmarshaling, etc.)
3. Update flags.LatestFlag() to propagate the error: return result, err
4. Update CLI to exit with code 1 when error occurs

[coderabbitai]

A summary of the changes CodeRabbit can apply:

• Update flags/version.go to change latestRelease to return error (convert six error cases to fmt.Errorf with %w and return nil on success) and make LatestFlag capture, print accumulated output on failure and propagate the error; update cli.go to check LatestFlag's error and return exit code 1 on failure (0 on success).

• Update error handling and exit-code behavior: modify flags/version.go to change latestRelease(output *strings.Builder) -> latestRelease(... ) error and replace prints+returns with wrapped errors (add return nil on success), update LatestFlag() to capture/print any output and return (result, err), update cli.go to check LatestFlag error and return exit code 1 on failure (0 on success), and add CHANGE_SUMMARY.md documenting these changes.

• ✅ Create PR with these edits
• 📋 Get copyable edits