refactor(skills): move content-strategy catalogs to references

Keep the decision steps in SKILL.md and move catalogs, examples, and
checklists verbatim to references/ to reduce the context cost of loading the
skill.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

shared/skills/content-strategy/references/pillars-and-keywords.md

@@ -0,0 +1,78 @@
+# Content Pillars and Keyword Research
+
+## Content Pillars and Topic Clusters
+
+Content pillars are the 3-5 core topics your brand will own. Each pillar spawns a cluster of related content.
+
+Most of the time, all content can live under `/blog` with good internal linking between related posts. Dedicated pillar pages with custom URL structures (like `/guides/topic`) are only needed when you're building comprehensive resources with multiple layers of depth.
+
+### How to Identify Pillars
+
+1. **Product-led**: What problems does your product solve?
+2. **Audience-led**: What does your ICP need to learn?
+3. **Search-led**: What topics have volume in your space?
+4. **Competitor-led**: What are competitors ranking for?
+
+### Pillar Structure
+
+```
+Pillar Topic (Hub)
+├── Subtopic Cluster 1
+│   ├── Article A
+│   ├── Article B
+│   └── Article C
+├── Subtopic Cluster 2
+│   ├── Article D
+│   ├── Article E
+│   └── Article F
+└── Subtopic Cluster 3
+    ├── Article G
+    ├── Article H
+    └── Article I
+```
+
+### Pillar Criteria
+
+Good pillars should:
+- Align with your product/service
+- Match what your audience cares about
+- Have search volume and/or social interest
+- Be broad enough for many subtopics
+
+---
+
+## Keyword Research by Buyer Stage
+
+Map topics to the buyer's journey using proven keyword modifiers:
+
+### Awareness Stage
+Modifiers: "what is," "how to," "guide to," "introduction to"
+
+Example: If customers ask about project management basics:
+- "What is Agile Project Management"
+- "Guide to Sprint Planning"
+- "How to Run a Standup Meeting"
+
+### Consideration Stage
+Modifiers: "best," "top," "vs," "alternatives," "comparison"
+
+Example: If customers evaluate multiple tools:
+- "Best Project Management Tools for Remote Teams"
+- "Asana vs Trello vs Monday"
+- "Basecamp Alternatives"
+
+### Decision Stage
+Modifiers: "pricing," "reviews," "demo," "trial," "buy"
+
+Example: If pricing comes up in sales calls:
+- "Project Management Tool Pricing Comparison"
+- "How to Choose the Right Plan"
+- "[Product] Reviews"
+
+### Implementation Stage
+Modifiers: "templates," "examples," "tutorial," "how to use," "setup"
+
+Example: If support tickets show implementation struggles:
+- "Project Template Library"
+- "Step-by-Step Setup Tutorial"
+- "How to Use [Feature]"