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/27-seo-ai-visibility/desktop/SKILL.md

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+---
+name: seo-ai-visibility
+description: |
+  AI search visibility and brand radar monitoring. Tracks how a brand appears
+  in AI-generated search answers using Ahrefs Brand Radar APIs.
+  Triggers: AI search, AI visibility, brand radar, AI citations,
+  share of voice, AI answers, AI mentions.
+---
+
+# SEO AI Visibility & Brand Radar
+
+Monitor and analyze brand visibility in AI-generated search results. This skill uses Ahrefs Brand Radar APIs to track impressions, mentions, share of voice, cited domains, cited pages, and AI response content.
+
+## Capabilities
+
+### AI Visibility Tracking
+- **Impressions Overview** - How often the brand appears in AI answers
+- **Mentions Overview** - Brand mention frequency across AI engines
+- **Share of Voice (SOV)** - Brand's share vs competitors in AI search
+- **Historical Trends** - Impressions, mentions, and SOV over time
+- **Competitor Comparison** - Side-by-side AI visibility metrics
+
+### AI Citation Analysis
+- **AI Response Analysis** - Content and sentiment of AI mentions
+- **Cited Domains** - Which source domains AI engines reference
+- **Cited Pages** - Specific URLs that get cited in AI answers
+- **Citation Ranking** - Frequency-based ranking of citations
+- **Sentiment Analysis** - Positive/neutral/negative distribution
+
+## Workflow
+
+1. **Input**: User provides target domain and optional competitors
+2. **Data Collection**: Fetch metrics from Ahrefs Brand Radar APIs
+3. **Analysis**: Calculate trends, compare competitors, analyze sentiment
+4. **Recommendations**: Generate actionable Korean-language recommendations
+5. **Output**: JSON report and Notion database entry
+
+## Ahrefs MCP Tools
+
+| Tool | Purpose |
+|------|---------|
+| `brand-radar-ai-responses` | AI-generated responses mentioning brand |
+| `brand-radar-cited-domains` | Domains cited in AI answers |
+| `brand-radar-cited-pages` | Specific pages cited in AI answers |
+| `brand-radar-impressions-history` | Impression trend over time |
+| `brand-radar-impressions-overview` | Current impression metrics |
+| `brand-radar-mentions-history` | Mention trend over time |
+| `brand-radar-mentions-overview` | Current mention metrics |
+| `brand-radar-sov-history` | Share of voice trend |
+| `brand-radar-sov-overview` | Current share of voice |
+
+## Notion Output
+
+All reports are saved to the OurDigital SEO Audit Log:
+- **Database ID**: `2c8581e5-8a1e-8035-880b-e38cefc2f3ef`
+- **Category**: AI Search Visibility
+- **Audit ID Format**: AI-YYYYMMDD-NNN
+- **Language**: Korean (technical terms in English)
+
+## Example Queries
+
+- "example.com의 AI 검색 가시성을 분석해줘"
+- "AI search visibility for example.com with competitors"
+- "브랜드 레이더 분석: example.com vs competitor.com"
+- "AI 인용 분석 - 어떤 페이지가 AI 답변에서 인용되나요?"
+- "Share of Voice in AI search for our domain"