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/21-seo-position-tracking/desktop/SKILL.md

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+---
+name: seo-position-tracking
+description: |
+  Keyword position tracking and ranking monitoring via Ahrefs Rank Tracker.
+  Triggers: rank tracking, position monitoring, keyword rankings, visibility score, ranking report, 키워드 순위, 순위 추적.
+---
+
+# SEO Position Tracking
+
+## Purpose
+
+Monitor keyword ranking positions, detect significant changes, calculate visibility scores, and compare against competitors using Ahrefs Rank Tracker data. Provides actionable alerts for ranking drops and segment-level performance breakdown.
+
+## Core Capabilities
+
+1. **Position Monitoring** - Retrieve current keyword ranking positions from Ahrefs Rank Tracker projects
+2. **Change Detection** - Detect significant position changes with configurable threshold alerts (severity: critical/high/medium/low)
+3. **Visibility Scoring** - Calculate weighted visibility scores using CTR-curve model (position 1 = 30%, position 2 = 15%, etc.)
+4. **Brand/Non-brand Segmentation** - Automatically classify keywords by brand relevance and search intent type
+5. **Competitor Comparison** - Compare keyword overlap, position gaps, and visibility scores against competitors
+
+## MCP Tool Usage
+
+### Ahrefs Rank Tracker Tools
+```
+mcp__ahrefs__rank-tracker-overview: Get rank tracking overview with current positions
+mcp__ahrefs__rank-tracker-competitors-overview: Compare rankings against competitors
+mcp__ahrefs__rank-tracker-competitors-pages: Competitor page-level ranking data
+mcp__ahrefs__rank-tracker-competitors-stats: Detailed competitor ranking statistics
+mcp__ahrefs__rank-tracker-serp-overview: SERP details for tracked keywords
+mcp__ahrefs__management-projects: List available Ahrefs projects
+mcp__ahrefs__management-project-keywords: Get tracked keywords for a project
+```
+
+### Notion for Report Storage
+```
+mcp__notion__notion-create-pages: Save tracking reports to SEO Audit Log
+mcp__notion__notion-update-page: Update existing tracking entries
+```
+
+## Workflow
+
+### Phase 1: Data Collection
+1. Identify Ahrefs project via `management-projects`
+2. Retrieve tracked keywords via `management-project-keywords`
+3. Fetch current positions via `rank-tracker-overview`
+4. Fetch competitor data via `rank-tracker-competitors-overview` (if requested)
+
+### Phase 2: Analysis
+1. Detect position changes against previous period
+2. Generate alerts for changes exceeding threshold
+3. Calculate visibility score weighted by search volume and CTR curve
+4. Segment keywords into brand/non-brand and by intent type
+5. Compare positions against each competitor
+
+### Phase 3: Reporting
+1. Compile position distribution (top3/top10/top20/top50/top100)
+2. Summarize changes (improved/declined/stable/new/lost)
+3. List alerts sorted by severity and search volume
+4. Generate segment-level breakdown
+5. Save report to Notion SEO Audit Log database
+
+## Output Format
+
+```json
+{
+  "target": "https://example.com",
+  "total_keywords": 250,
+  "visibility_score": 68.5,
+  "positions": {
+    "top3": 15,
+    "top10": 48,
+    "top20": 92,
+    "top50": 180,
+    "top100": 230
+  },
+  "changes": {
+    "improved": 45,
+    "declined": 30,
+    "stable": 155,
+    "new": 12,
+    "lost": 8
+  },
+  "alerts": [
+    {
+      "keyword": "example keyword",
+      "old_position": 5,
+      "new_position": 15,
+      "change": -10,
+      "volume": 5400,
+      "severity": "high"
+    }
+  ],
+  "segments": {
+    "brand": {"keywords": 30, "avg_position": 2.1},
+    "non_brand": {"keywords": 220, "avg_position": 24.5}
+  }
+}
+```
+
+## Notion Output (Required)
+
+All tracking reports MUST be saved to OurDigital SEO Audit Log:
+- **Database ID**: `2c8581e5-8a1e-8035-880b-e38cefc2f3ef`
+- **Properties**: Issue (title), Site (url), Category (Position Tracking), Priority, Found Date, Audit ID
+- **Language**: Korean with English technical terms
+- **Audit ID Format**: RANK-YYYYMMDD-NNN