Type Alias Color

A cell color value. Matches the Rust Color enum serialized with #[serde(untagged)]:

• string → Color::Rgb("#RRGGBB")
• [number, number] → Color::Theme(index, tint)
• absent/undefined → Color::None (field omitted via skip_serializing_if)

Pass to model.resolveColor(color) to get the final CSS hex string.