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/USER-WP-0009-postgres-durable-store-requirements.md

@@ -2,7 +2,7 @@
 id: USER-WP-0009
 type: workplan
 title: "Postgres Durable Store Consumer Requirements"
-domain: netkingdom
+domain: communication
 repo: user-engine
 status: finished
 owner: codex