Delete /create-epics-stories and update all references

Removes the deprecated skill entirely and updates every reference across:
- README.md, UPGRADING.md (skill count + file lists)
- docs/WORKFLOW-GUIDE.md (pipeline diagrams, step descriptions, command reference)
- docs/examples/skill-flow-diagrams.md, session-*.md
- docs/architecture/tr-registry.yaml
- tests/skills/catalog.yaml
- .claude/skills: adopt, content-audit, create-control-manifest,
  skill-test, story-readiness
- .claude/docs: skills-reference.md, quick-start.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/create-control-manifest/SKILL.md

@@ -235,7 +235,7 @@ These APIs are deprecated or unverified for [engine + version]:
 
 After writing the manifest:
 
-- If epics/stories don't exist yet: "Run `/create-epics-stories` — programmers
+- If epics/stories don't exist yet: "Run `/create-epics layer: foundation` then `/create-stories [epic-slug]` — programmers
   can now use this manifest when writing story implementation notes."
 - If this is a regeneration (manifest already existed): "Updated. Recommend
   notifying the team of changed rules — especially any new Forbidden entries."