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/tools/ahrefs.md

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+# Ahrefs Brand Radar MCP Tools
+
+## brand-radar-impressions-overview
+Get current AI search impression metrics for a target domain. Returns total impressions, change percentage, and breakdown by AI engine.
+
+**Parameters:**
+- `target` (required): Domain to analyze (e.g., "example.com")
+
+## brand-radar-impressions-history
+Get historical AI search impression data over time. Returns time-series data points with date and impression values.
+
+**Parameters:**
+- `target` (required): Domain to analyze
+
+## brand-radar-mentions-overview
+Get current AI mention metrics for a target domain. Returns total mentions, change percentage, and breakdown.
+
+**Parameters:**
+- `target` (required): Domain to analyze
+
+## brand-radar-mentions-history
+Get historical AI mention data over time. Returns time-series data points with date and mention values.
+
+**Parameters:**
+- `target` (required): Domain to analyze
+
+## brand-radar-sov-overview
+Get Share of Voice overview in AI search for a target domain. Returns brand SOV percentage and competitor SOV data.
+
+**Parameters:**
+- `target` (required): Domain to analyze
+
+## brand-radar-sov-history
+Get historical Share of Voice data over time. Returns time-series SOV data points.
+
+**Parameters:**
+- `target` (required): Domain to analyze
+
+## brand-radar-ai-responses
+Get AI-generated responses that mention the brand. Returns query, response text, sentiment, and source engine for each response.
+
+**Parameters:**
+- `target` (required): Domain to analyze
+
+## brand-radar-cited-domains
+Get domains cited in AI answers related to the brand. Returns domain name, citation count, topics, and share percentage.
+
+**Parameters:**
+- `target` (required): Domain to analyze
+
+## brand-radar-cited-pages
+Get specific pages cited in AI answers. Returns URL, title, citation count, context snippet, and topics.
+
+**Parameters:**
+- `target` (required): Domain to analyze