Resolve extraction reference bindings from config

docs/internal/pipeline.md

@@ -30,6 +30,14 @@ before execution:
 
 The CLI writes the resolved pipeline and digest to diagnostics.
 
+Pipeline profiles and artifact lanes may include reference binding maps keyed by
+extractor reference slot name. During resolution, pipeline-level bindings act as
+defaults for selected lanes whose extractor declares the slot, lane-level
+bindings override or add lane bindings, and runtime unbinds can remove bindings.
+Resolution validates bindings against extractor specs and records lane-scoped
+binding metadata. It does not read reference files or include reference bytes in
+source digests.
+
 ## Registries And Module Specs
 
 `pipeline.Registries` holds concrete constructors for execution. A