WIP multiple sections

docs/spec/09-distribution-board-components-and-protection-groups.md

@@ -739,6 +739,9 @@ Acceptance:
 
 ### E. Editor Projection and Editing
 
+Status: In progress. The complete tree read model E1 and pure structural
+projection E2a are complete. Grid rendering and editing remain pending.
+
 - render fixed header components
 - render group components and circuit blocks
 - render sortable auxiliary footer components
@@ -746,6 +749,17 @@ Acceptance:
 - add type-dependent protection editing
 - keep spreadsheet selection, keyboard and drag behavior coherent
 
+Implemented in E1/E2a:
+
+- the tree response exposes fixed header, group and auxiliary footer
+  components plus both one-to-one protection layers
+- a pure projection produces the stable order header, complete groups and
+  footer without mixing zones
+- each group keeps its heading, optional protection components, complete
+  circuit blocks and free placeholder together
+- empty groups remain visible and circuit device rows remain owned by their
+  circuit block
+
 Acceptance:
 
 - the visible order is header, groups, footer