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/adopt/SKILL.md

@@ -116,7 +116,7 @@ If `design/gdd/systems-index.md` exists:
 
 1. **Parenthetical status values** — Grep for any Status cell containing
    parentheses: `"Needs Revision ("`, `"In Progress ("`, etc.
-   These break exact-string matching in `/gate-check`, `/create-epics-stories`,
+   These break exact-string matching in `/gate-check`, `/create-stories`,
    and `/architecture-review`. **BLOCKING.**
 
 2. **Valid status values** — check that Status column values are only from:
@@ -240,7 +240,7 @@ Stories audited: [N]
 
 Gap counts:
   BLOCKING: [N] — template skills will malfunction without these fixes
-  HIGH:     [N] — unsafe to run /create-epics-stories or /story-readiness
+  HIGH:     [N] — unsafe to run /create-stories or /story-readiness
   MEDIUM:   [N] — quality degradation
   LOW:      [N] — optional improvements
 
@@ -350,7 +350,7 @@ If ADRs are missing Status fields:
 
 If GDDs are missing Acceptance Criteria:
 > "The most important GDD gap is missing Acceptance Criteria — without these,
-> `/create-epics-stories` can't generate stories. Shall I start with
+> `/create-stories` can't generate stories. Shall I start with
 > `design/gdd/[highest-priority-system].md` using `/design-system retrofit`?"
 
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