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/post-templates.md

@@ -2,6 +2,12 @@
 
 Ready-to-use templates for different platforms and content types.
 
+## Contents
+- LinkedIn Post Templates (The Story Post, The Contrarian Take, The List Post, The How-To)
+- Twitter/X Thread Templates (The Tutorial Thread, The Story Thread, The Breakdown Thread)
+- Instagram Templates (The Carousel Hook, The Reel Script)
+- Hook Formulas (Curiosity Hooks, Story Hooks, Value Hooks, Contrarian Hooks, Social Proof Hooks)
+
 ## LinkedIn Post Templates
 
 ### The Story Post