feat: add site-architecture skill for website structure planning

Fills the gap between content strategy and SEO skills — covers page
hierarchy, navigation design, URL structure, and internal linking.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -45,6 +45,7 @@ Skills are markdown files that give AI agents specialized knowledge and workflow
 | [schema-markup](skills/schema-markup/) | When the user wants to add, fix, or optimize schema markup and structured data on their site. Also use when the user... |
 | [seo-audit](skills/seo-audit/) | When the user wants to audit, review, or diagnose SEO issues on their site. Also use when the user mentions "SEO... |
 | [signup-flow-cro](skills/signup-flow-cro/) | When the user wants to optimize signup, registration, account creation, or trial activation flows. Also use when the... |
+| [site-architecture](skills/site-architecture/) | When the user wants to plan, map, or restructure their website's page hierarchy, navigation, URL structure, or internal... |
 | [social-content](skills/social-content/) | When the user wants help creating, scheduling, or optimizing social media content for LinkedIn, Twitter/X, Instagram,... |
 <!-- SKILLS:END -->
 
@@ -166,6 +167,7 @@ You can also invoke skills directly:
 - `seo-audit` - Technical and on-page SEO
 - `ai-seo` - AI search optimization (AEO, GEO, LLMO)
 - `programmatic-seo` - Scaled page generation
+- `site-architecture` - Page hierarchy, navigation, URL structure
 - `competitor-alternatives` - Comparison and alternative pages
 - `schema-markup` - Structured data