plot styles: the CTB/STB model and codec come from the codec crate

Cargo: codec d36331d, kernel 60f086b, graph 74aac56.

The table model and its file codec now live in `codec::plot_style`
(opencadcodec#53) and are re-exported here. What stays is where tables
come from: the plot styles folder, the session registry, the shipped
tables, and saving to disk, as the `PlotStyleTableExt` trait.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/scene/view/render.rs

@@ -1,6 +1,7 @@
 // GPU rendering primitives, shader::Program / shader::Primitive impls,
 // and entity render-style helpers for the Scene.
 
+use crate::io::plot_style::PlotStyleTableExt as _;
 use codec::tables::LineType;
 use codec::types::{Color as AcadColor, LineWeight};
 use codec::{CadDocument, EntityType, Handle};