Project wallpaper and color can't be read or set through the API or CLI #864

What I'm trying to do

We create projects automatically from a script and want each one to look the same as the ones we set up by hand. Everything else in the setup now works through the API (name, description, everyone-in-the-account access, tool names, turning tools on and off, message categories, folders, to-do lists). The project's look is the one piece that can't be scripted.

What happens

Wallpaper

• After setting a wallpaper on a project in the web app, GET /projects/<id>.json returns no wallpaper or background field. The only change is updated_at.
• The image's storage URL (storage.3.basecamp.com/.../rails/active_storage/...) does not appear in the project, its timeline, its people, its uploads, or search.
• There is no wallpaper endpoint that I could find, so a script can neither read the wallpaper nor copy it to a new project.

Color

• GET /projects/<id>.json includes color (for example "green"), so it can be read.
• PUT /projects/<id>.json with {"name": "...", "color": "blue"} returns success, but the color is unchanged. The field is silently ignored.

CLI

• basecamp projects update accepts only --name and --description.

What would help

1. A wallpaper field on the project (read), and a way to set or clear it through the API: upload an image, or reuse an attachable sgid from basecamp attach.
2. color writable on PUT /projects/<id>.json, or an error when it is sent and ignored.
3. basecamp projects update --color and --wallpaper <file>.
4. Documentation on whether a template's wallpaper and color carry over to projects created from it, so automation can rely on templates if the fields stay read only.

Environment

basecamp CLI 0.13.0 on macOS, OAuth (Launchpad) token, Basecamp account with owner and admin rights.