Normalize agent instructions and workplan frontmatter (STATE-WP-0067)

- Align agent files with on-disk workplan prefixes (infer from workplan ids)
- Set workplan domain to registered domain_slug; add topic_slug where applicable
- Repair frontmatter delimiter formatting; migrate legacy task status literals
- Regenerate AGENTS.md, CLAUDE.md, and .claude/rules from State Hub templates

workplans/kaizen-agentic-WP-0007-agent-authoring-doc-generation.md

@@ -2,7 +2,7 @@
 id: KAIZEN-WP-0007
 type: workplan
 title: "Agent Authoring & Doc Generation (v1.4.0)"
-domain: custodian
+domain: agents
 repo: kaizen-agentic
 status: done
 owner: kaizen-agentic
@@ -36,8 +36,7 @@ tasks:
 - id: T06
   state_hub_task_id: 6715aa6f-1ee0-4f22-9249-f1cd41763cd1
   status: done
-  title: Docs, CLI cheat sheet, CHANGELOG for v1.4.0
----
+  title: Docs, CLI cheat sheet, CHANGELOG for v1.4.0---
 
 # KAIZEN-WP-0007 — Agent Authoring & Doc Generation