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/19-seo-keyword-strategy/code/scripts/requirements.txt

@@ -0,0 +1,20 @@
+# 19-seo-keyword-strategy dependencies
+# Install: pip install -r requirements.txt
+
+# HTTP & Async
+requests>=2.31.0
+aiohttp>=3.9.0
+
+# Data Processing
+pandas>=2.1.0
+
+# NLP / Text Similarity
+scikit-learn>=1.3.0
+
+# Async & Retry
+tenacity>=8.2.0
+tqdm>=4.66.0
+
+# Environment & CLI
+python-dotenv>=1.0.0
+rich>=13.7.0