Render R2: persist named render setups without re-evaluating geometry (#667)

render.settings.set saves validated named render setups (camera, output size, exposure, environment) as one undo step, and render.settings.get reads them back without applying a camera. When validated render settings are the only change, the engine keeps the evaluated model instead of rebuilding it. Setups are saved under design format 21; format-20 designs read as having none. Fixes #658; refs #620.

Contributed by @0xlillith.

Co-authored-by: lillith <[email protected]>

ROADMAP.md

@@ -89,6 +89,11 @@ PCB / Package, Render, Animation, Simulation, Manufacture/CAM, Drawings.
 
 ## Render foundation
 
+- R2 adds bounded named render setups in document format 21 and the read/save
+  `render.settings.get/set` commands. Proven render-only changes preserve geometry
+  and prepared world data through undo/redo and checkpoint restore. This slice does
+  not add a Render workspace, PBR, environments or image jobs; see
+  [settings and refresh policy](docs/render-settings.md).
 - Bounded PNG/JPEG texture admission (#900) validates in-memory sources and returns
   completed RGBA8 pixels with explicit color/data roles. It is an input utility only:
   ICC/16-bit normalization, local wood mapping, resource persistence and the renderer