feat(cad): integrate standard codec coverage

Render, edit, query, select, and explode newly decoded standard entity variants. Pin acadifc de8d6b5 and preserve None color semantics.

src/ui/color_select.rs

@@ -45,6 +45,7 @@ pub fn color_to_aci_string(c: AcadColor) -> String {
     match c {
         AcadColor::ByBlock => "0".to_string(),
         AcadColor::ByLayer => "256".to_string(),
+        AcadColor::None => "257".to_string(),
         AcadColor::Index(i) => i.to_string(),
         AcadColor::Rgb { .. } => "256".to_string(),
     }
@@ -55,6 +56,7 @@ pub fn aci_string_to_color(s: &str) -> AcadColor {
     match s.trim().parse::<i16>().unwrap_or(256) {
         0 => AcadColor::ByBlock,
         256 => AcadColor::ByLayer,
+        257 => AcadColor::None,
         n if (1..=255).contains(&n) => AcadColor::Index(n as u8),
         _ => AcadColor::ByLayer,
     }

src/ui/properties.rs

@@ -1356,6 +1356,7 @@ fn picker_text_btn(label: &str, msg: Message) -> Element<'_, Message> {
 /// Returns an (iced::Color swatch_bg, display_label) pair for an AcadColor.
 pub fn acad_color_display(c: AcadColor) -> (Color, &'static str) {
     match c {
+        AcadColor::None => (Color::TRANSPARENT, "None"),
         AcadColor::ByLayer => (
             Color {
                 r: 0.35,

src/ui/style/mlstyle.rs

@@ -38,6 +38,7 @@ pub fn view_window<'a>(
             .map(|(idx, e)| {
                 let color_str = match &e.color {
                     acadrust::types::Color::ByLayer => "ByLayer".into(),
+                    acadrust::types::Color::None => "None".into(),
                     acadrust::types::Color::ByBlock => "ByBlock".into(),
                     acadrust::types::Color::Index(i) => format!("ACI {i}"),
                     acadrust::types::Color::Rgb { r, g, b } => format!("#{r:02X}{g:02X}{b:02X}"),

src/ui/window/attribute_editor.rs

@@ -116,6 +116,7 @@ const COLOR_OPTIONS: &[&str] = &[
 pub fn color_label(c: AcadColor) -> String {
     match c {
         AcadColor::ByLayer => "ByLayer".into(),
+        AcadColor::None => "None".into(),
         AcadColor::ByBlock => "ByBlock".into(),
         AcadColor::Index(1) => "Red".into(),
         AcadColor::Index(2) => "Yellow".into(),