Create circuits with rows atomically

docs/circuit-list-editor-api.md

@@ -44,6 +44,8 @@ Response sketch:
 
 - `POST /projects/:projectId/circuit-lists/:circuitListId/circuits`
   - create circuit in list/section
+- `POST /projects/:projectId/circuit-lists/:circuitListId/circuits-with-device-rows`
+  - atomically create one circuit and one or more initial device rows
 - `PATCH /circuits/:circuitId`
   - update circuit-level fields (BMK, protection, cable, reserve flag, etc.)
 - `DELETE /circuits/:circuitId`

docs/circuit-list-editor-interactions.md

@@ -56,6 +56,7 @@ Each section has a trailing placeholder row showing `-frei-` in BMK column:
 
 - serves as drop target for creating new circuits from project devices or moved rows
 - editable placeholder cells can create a new circuit + first row through the same edit command flow
+- a new circuit and its initial row(s) are created in one SQLite transaction
 
 ## Add Circuit Behavior
 
@@ -68,6 +69,7 @@ Intent is separated by drag source type:
 
 - project device drag:
   - drop to section/placeholder -> create new circuit with linked row
+  - the new circuit and linked row are committed atomically
   - drop to existing circuit row -> append row to that circuit
   - lighting devices are accepted only by the lighting section
   - other devices are accepted only by the section matching their phase type