Separate stage order from invalidation dependencies

docs/internal/stage-render.md

@@ -3,6 +3,10 @@
 ## Purpose
 
 Render Markdown transcript artifacts from normalized JSON transcripts via Seriatim.
+It runs after `trim` and before `extract` in the canonical sequence. Render and
+extract are independent sibling consumers: replacing render output does not
+invalidate extraction, but it does invalidate succeeded analysis and delivery
+records that may consume rendered transcripts.
 
 ## Inputs