refactor(render): trim Atlas and Shaders

render/Atlas.h

@@ -8,7 +8,9 @@ namespace vf {
 
 // A procedurally generated texture-array atlas: one RGBA tile per layer,
 // indexed by the tile ids that Block.h assigns to each face. Built in code so
-// the demo has no binary asset dependency.
+// the demo has no binary asset dependency. The colours and the patterns come
+// from vf::TilePalette and are drawn by vf::TileSampler, both in core/ and both
+// under test; this header only describes the buffer they are written into.
 struct Atlas {
     int tileSize = 16;
     int layers = tileCount;