Document completed LLM and reference expansion

docs/config.md

@@ -199,6 +199,14 @@ bindings. They override pipeline-level defaults for slots declared by the chunk
 or normalizer module. Extractor-local references apply only to the extractor,
 and normalizer-local references apply only to the normalizer.
 
+Stage-local reference fields use the same map shape at:
+
+- `pipelines.<id>.chunk.references`
+- `pipelines.<id>.artifacts.<lane>.extract.references`
+- `pipelines.<id>.artifacts.<lane>.normalize.references`
+
+Each binding is valid only when that target module declares the slot.
+
 ## Module Bindings
 
 Every module binding may use shorthand: