Add SEO skills 19-28, 31-32 with full Python implementations

12 new skills: Keyword Strategy, SERP Analysis, Position Tracking,
Link Building, Content Strategy, E-Commerce SEO, KPI Framework,
International SEO, AI Visibility, Knowledge Graph, Competitor Intel,
and Crawl Budget. ~20K lines of Python across 25 domain scripts.
Updated skill 11 pipeline table and repo CLAUDE.md.
Enhanced skill 18 local SEO workflow from jamie.clinic audit.

Note: Skill 26 hreflang_validator.py pending (content filter block).

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

custom-skills/20-seo-serp-analysis/desktop/skill.yaml

@@ -0,0 +1,14 @@
+# Skill metadata (extracted from SKILL.md frontmatter)
+
+name: seo-serp-analysis
+description: |
+  SERP analysis for Google and Naver. Triggers: SERP analysis, search results, featured snippet, SERP features, Naver SERP.
+
+# Optional fields
+allowed-tools:
+  - mcp__ahrefs__*
+  - mcp__notion__*
+  - WebSearch
+  - WebFetch
+
+# triggers: []  # TODO: Extract from description