Use in-vocabulary capability tags

capability_families in repo-classification.allowed.yaml is a fixed list;
'experience' and 'documents' are not in it. Replaced with 'traceability' and
'participation', both in the knowledge_and_evidence family and both accurate:
this repository owns the evidence chain and the surface on which a human takes
part in a decision.

'decision-support' is in the recommended vocabulary but is still not used, for
the statute §8 reason given in the previous commit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V3W1dQG7GFFM9d94jFx7iR

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 1565372@bnt-lap001
Assistant-Session: 16bb2f25-b34c-49ef-8e94-5fec3567a568

.repo-classification.yaml

@@ -10,8 +10,8 @@ repo_classification:
     - governance
     - evidence
     - identity
-    - experience
-    - documents
+    - traceability
+    - participation
     - audit
   business_stake:
     - technology