fix(render): preserve transparency inheritance

Resolve ByBlock alpha independently from color and keep explicit opaque values from falling back to layer transparency.

Pin the matching cadcodec API across desktop, plugin, and web targets.

Refs HakanSeven12/cadcodec#2

src/scene/cache/properties.rs

@@ -1,4 +1,4 @@
-use acadrust::{EntityType, Handle};
+use acadrust::{EntityType, Handle, Transparency};
 use crate::t;
 
 use crate::scene::model::object::{PropSection, PropValue, Property};
@@ -10,15 +10,12 @@ pub fn general_section(entity: &EntityType) -> PropSection {
     } else {
         common.linetype.clone()
     };
-    // Alpha 0 is ByLayer, Alpha 1 is ByBlock; show them by name and fall back
-    // to a rounded percentage for explicit values.
-    let transp_display = match common.transparency.alpha() {
-        0 => "ByLayer".to_string(),
-        1 => "ByBlock".to_string(),
-        alpha => format!(
-            "{}",
-            (alpha as f64 / 255.0 * 100.0).round() as u32
-        ),
+    let transp_display = match common.transparency {
+        Transparency::ByLayer => "ByLayer".to_string(),
+        Transparency::ByBlock => "ByBlock".to_string(),
+        Transparency::Explicit(alpha) => {
+            ((alpha as f64 / 255.0 * 100.0).round() as u32).to_string()
+        }
     };
 
     // Hyperlink is stored in XDATA under the "PE_URL" application.