feat: created the staging area for state merges per super-step and created the built-in reducers (and their application) for the state merge phase of a super step

src/graph/mod.rs

@@ -5,7 +5,9 @@ pub mod llm;
 pub mod logging;
 pub mod parser;
 pub mod rag;
+pub mod reducer;
 pub mod script;
+pub mod staging;
 pub mod state;
 pub mod structured;
 pub mod types;