Implement optional Skia codec adapter (#41)

crates/libremetaverse-imaging-skia/src/lib.rs

@@ -2,20 +2,15 @@
 
 extern crate self as libremetaverse_imaging_skia;
 
-pub mod backend {
-    /// Project-owned bitmap boundary; no `SkiaSharp` API is copied.
-    pub struct SKBitmap;
-}
+pub mod backend;
 
 mod generated;
+mod skia_codec;
 
 pub use generated::*;
 pub use libremetaverse_imaging as imaging;
 pub use libremetaverse_types::Error;
 
-// The native codec abstraction requires an explicit implementation. Until the
-// optional Skia adapter is ported, forward through its cataloged typed-failure
-// method rather than manufacturing an image or silently accepting input.
 impl libremetaverse_imaging::ITextureCodec for SkiaTextureCodec {
     fn decode(
         &self,