Restructure skill numbering: SEO 11-30, GTM 60-69, reserve 19-28 for future skills

Renumber 12 existing skills to new ranges:
- SEO: 11→13, 12→18, 13→16, 14→17, 15→14, 16→15, 17→29, 18→30, 19→12
- GTM: 20→60, 21→61, 22→62

Update cross-references in gateway architect/builder skills, GTM guardian
README, CLAUDE.md (skill tables + directory layout), and AGENTS.md
(domain routing ranges).

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

custom-skills/60-gtm-audit/code/scripts/requirements.txt

@@ -0,0 +1 @@
+playwright>=1.40.0

custom-skills/60-gtm-audit/code/scripts/setup.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+# GTM Audit Tool Setup Script
+
+echo "🔧 Setting up GTM Audit Tool..."
+
+# Check Python
+if ! command -v python3 &> /dev/null; then
+    echo "❌ Python 3 is required but not installed."
+    exit 1
+fi
+
+echo "✅ Python 3 found"
+
+# Install dependencies
+echo "📦 Installing Python dependencies..."
+pip install -r requirements.txt
+
+# Install Playwright browsers
+echo "🌐 Installing Playwright browsers..."
+playwright install chromium
+
+echo ""
+echo "✅ Setup complete!"
+echo ""
+echo "Usage:"
+echo "  python gtm_audit.py --url 'https://example.com' --journey full"
+echo ""
+echo "For Claude Code:"
+echo "  claude"
+echo "  > Run a GTM audit on https://example.com"