Render: bounded PNG/JPEG texture input admission (#909)

Bounded in-memory PNG/JPEG texture decoding with explicit base-colour/data-map roles; RGBA8 pixels are published only after a complete decode. Input only: no material assignment, GPU shading or persistence. Refs #900.

Contributed by @0xlillith.

Co-authored-by: lillith <35337584+0xlillith@users.noreply.github.com>

crates/render/src/lib.rs

@@ -10,6 +10,7 @@ mod curve_display;
 pub mod lighting;
 mod raster;
 pub mod surface;
+pub mod texture_input;
 
 pub use backend::{
     Availability, BackendDescriptor, BackendId, ExecutorDescriptor, ExecutorId, MAX_RENDER_ID_BYTES, RenderFeature, RenderFormat, RenderLimits,