Standardize unimplemented API failures

crates/libremetaverse-rendering-mesh-foundry/src/generated.rs

@@ -3,7 +3,7 @@
 #![allow(non_camel_case_types)]
 
 /// `class` shim for C# `LibreMetaverse.Rendering.MeshFoundry`; members remain intentionally unimplemented.
-#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct MeshFoundry;
 impl MeshFoundry {
     pub const CSHARP_NAME: &'static str = "LibreMetaverse.Rendering.MeshFoundry";

crates/libremetaverse-rendering-mesh-foundry/src/lib.rs

@@ -8,3 +8,4 @@ pub use libremetaverse_imaging as imaging;
 pub use libremetaverse_prim_mesher as prim_mesher;
 pub use libremetaverse_structured_data as structured_data;
 pub use libremetaverse_types as types;
+pub use libremetaverse_types::NotImplemented as Error;