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>

tests/skills/catalog.yaml

@@ -51,7 +51,21 @@ skills:
     priority: critical
 
   # High — pipeline-critical skills
-  - name: create-epics-stories
+  - name: create-epics
+    spec: ""
+    last_static: ""
+    last_static_result: ""
+    last_spec: ""
+    last_spec_result: ""
+
+  - name: create-stories
+    spec: ""
+    last_static: ""
+    last_static_result: ""
+    last_spec: ""
+    last_spec_result: ""
+
+  - name: dev-story
     spec: ""
     last_static: ""
     last_static_result: ""