Checklist

• I added a descriptive title
• I searched open requests and couldn't find a duplicate

What is the idea?

Support --anaconda-upload flag to upload built v1 packages, and respect --no-anaconda-upload flag.

Why is this needed?

Users expect automatic upload after successful builds.

What should happen?

1. Check if upload enabled after successful build (parsed_args.anaconda_upload)
2. Reuse conda-build's existing upload code
3. Pass through upload options (--token, --user, --label)
4. Handle errors gracefully (warn, don't fail)
5. Add tests and documentation

Additional Context

• Default is to upload (controlled by context.binstar_upload)
• Use --no-anaconda-upload to disable