Add D&D NPC interaction artifact codec

docs/roadmap/future.md

@@ -18,28 +18,10 @@ not as committed release dates.
 
 ### Extract NPC Interactions
 
-- Add an ordered NPC-interaction artifact that records how an identifiable NPC
-  participates in the session without adding occurrence-level state to the
-  normalized NPC registry. Use `npc-interactions` as the working lane and
-  product name; the exact artifact kind may be finalized with its contract.
-- Keep each record minimal: canonical NPC `name`, one bounded interaction
-  `kind`, and transcript `source_refs` supporting both the identity and
-  classification.
-- Start with the mutually exclusive vocabulary `mentioned`,
-  `noncombat_presence`, `dialogue`, `combat_ally`, `combat_opponent`, and
-  `other`. Define narrow inclusion rules and category precedence before
-  implementation so overlapping activity does not produce arbitrary labels.
-- Model interactions as ordered occurrences rather than one scalar NPC
-  category. The same NPC may therefore have separate records when the
-  transcript establishes distinct interactions, such as dialogue followed by
-  hostile combat.
-- Run NPC identity extraction first and provide its accepted names-only
-  projection to the interaction extractor for grounding. Registry names may
-  disambiguate identity but never establish that an interaction occurred, and
-  registry source references must not be copied into interaction evidence.
-- Evaluate category agreement, evidence sufficiency, duplicate behavior, and
-  smaller-model reliability on human-reviewed transcripts before expanding the
-  enum or adding additional fields.
+Add a minimal, ordered `dnd/npc-interactions` artifact after NPC identity
+extraction. The proposed contract, occurrence semantics, category policy,
+grounding rules, evidence requirements, and non-goals are defined in
+[D&D NPC Interactions](dnd-npc-interactions.md).
 
 ### Export Accepted Chunk Maps