fix: add table of contents to all reference files

Per Anthropic's Agent Skills best practices, reference files over
  100 lines should include a TOC so Claude can see full scope when
  previewing with partial reads. Added ## Contents section to all
  32 reference files.

skills/social-content/references/reverse-engineering.md

@@ -2,6 +2,11 @@
 
 Instead of guessing what works, systematically analyze top-performing content in your niche and extract proven patterns.
 
+## Contents
+- The 6-Step Framework (Niche ID, Scrape, Analyze, Playbook, Layer Voice, Convert)
+- The Formula
+- Reverse Engineering Checklist
+
 ## The 6-Step Framework
 
 ### 1. NICHE ID — Find Top Creators