Add feature roadmap and implementation plan for a D&D NPC extraction module

docs/roadmap/future.md

@@ -18,8 +18,10 @@ not as committed release dates.
 
 ### Add Sequential D&D Artifacts
 
-- Add NPC extraction, including identity, aliases, descriptions, relationships,
-  and source evidence suitable for use as later reference material.
+- Add the proposed [D&D NPC extraction and registry](dnd-npc-extraction.md) as
+  the next sequential artifact. It defines canonical identity, aliases,
+  descriptions, relationships, evidence, deterministic consolidation, and
+  direct reuse as spell-pipeline reference material.
 - Add combat-turn extraction with explicit event and source-reference
   semantics. Use earlier NPC output as a reference to improve participant
   identity and consistency.