Document the runtime delta modules where understanding needs it

node-graph/graph-craft/src/runtime_delta.rs

@@ -1,7 +1,11 @@
 use crate::document::{DocumentNode, NodeId, NodeInput};
 
+/// One mutation's worth of structural graph change, carrying its post-change data as plain runtime
+/// types. Constructed by the mutation itself; a compound mutation emits several. Consumed typed and
+/// unserialized by the compiler, and paired with `EditorDelta` metadata for storage staging.
 #[derive(Debug, Clone, PartialEq)]
 pub enum RuntimeDelta {
+	/// The node's nested network, if it implements one, rides inside the `DocumentNode`.
 	AddNode {
 		network_path: Vec<NodeId>,
 		node_id: NodeId,
@@ -12,6 +16,7 @@ pub enum RuntimeDelta {
 		node_id: NodeId,
 		node: Box<DocumentNode>,
 	},
+	/// Address-only: removal snapshots come from the storage layer's working registry.
 	RemoveNode {
 		network_path: Vec<NodeId>,
 		node_id: NodeId,