forked from 1b-agent/opencadstudio-upstream
- DocumentTab: bg_color / paper_bg_color Optional<[f32;4]> fields - view.rs: use custom color when set, fall back to defaults - BACKGROUND <r> <g> <b>: set model or paper-space background (0–255 RGB) - BACKGROUND RESET: restore default dark grey / paper grey Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>