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/14-seo-core-web-vitals/desktop/SKILL.md

@@ -0,0 +1,117 @@
+---
+name: seo-core-web-vitals
+description: |
+  Core Web Vitals analyzer for LCP, FID, CLS, and INP optimization recommendations.
+  Triggers: Core Web Vitals, page speed, LCP optimization, CLS fix, INP analysis.
+---
+
+# SEO Core Web Vitals
+
+## Purpose
+
+Analyze Core Web Vitals performance metrics and provide optimization recommendations.
+
+## Core Capabilities
+
+1. **LCP** - Largest Contentful Paint measurement
+2. **FID/INP** - Interactivity metrics
+3. **CLS** - Cumulative Layout Shift
+4. **Recommendations** - Optimization guidance
+
+## Metrics Thresholds
+
+| Metric | Good | Needs Work | Poor |
+|--------|------|------------|------|
+| LCP | ≤2.5s | 2.5-4s | >4s |
+| FID | ≤100ms | 100-300ms | >300ms |
+| CLS | ≤0.1 | 0.1-0.25 | >0.25 |
+| INP | ≤200ms | 200-500ms | >500ms |
+
+## Data Sources
+
+### Option 1: PageSpeed Insights (Recommended)
+Use external tool and input results:
+- Visit: https://pagespeed.web.dev/
+- Enter URL, run test
+- Provide scores to skill
+
+### Option 2: Research Best Practices
+```
+mcp__perplexity__search: "Core Web Vitals optimization [specific issue]"
+```
+
+## Workflow
+
+1. Request PageSpeed Insights data from user
+2. Analyze provided metrics
+3. Identify failing metrics
+4. Research optimization strategies
+5. Provide prioritized recommendations
+
+## Common LCP Issues
+
+| Cause | Fix |
+|-------|-----|
+| Slow server response | Improve TTFB, use CDN |
+| Render-blocking resources | Defer non-critical CSS/JS |
+| Slow resource load | Preload LCP image |
+| Client-side rendering | Use SSR/SSG |
+
+## Common CLS Issues
+
+| Cause | Fix |
+|-------|-----|
+| Images without dimensions | Add width/height attributes |
+| Ads/embeds without space | Reserve space with CSS |
+| Web fonts causing FOIT/FOUT | Use font-display: swap |
+| Dynamic content injection | Reserve space, use transforms |
+
+## Common INP Issues
+
+| Cause | Fix |
+|-------|-----|
+| Long JavaScript tasks | Break up tasks, use web workers |
+| Large DOM size | Reduce DOM nodes |
+| Heavy event handlers | Debounce, optimize listeners |
+| Third-party scripts | Defer, lazy load |
+
+## Output Format
+
+```markdown
+## Core Web Vitals: [URL]
+
+### Scores
+| Metric | Mobile | Desktop | Status |
+|--------|--------|---------|--------|
+| LCP | Xs | Xs | Good/Poor |
+| FID | Xms | Xms | Good/Poor |
+| CLS | X.XX | X.XX | Good/Poor |
+| INP | Xms | Xms | Good/Poor |
+
+### Overall Score
+- Mobile: X/100
+- Desktop: X/100
+
+### Priority Fixes
+1. [Highest impact recommendation]
+2. [Second priority]
+
+### Detailed Recommendations
+[Per-metric optimization steps]
+```
+
+## Limitations
+
+- Requires external PageSpeed Insights data
+- Lab data may differ from field data
+- Some fixes require developer implementation
+- Third-party scripts may be difficult to optimize
+
+## Notion Output (Required)
+
+All audit reports MUST be saved to OurDigital SEO Audit Log:
+- **Database ID**: `2c8581e5-8a1e-8035-880b-e38cefc2f3ef`
+- **Properties**: Issue (title), Site (url), Category, Priority, Found Date, Audit ID
+- **Language**: Korean with English technical terms
+- **Audit ID Format**: [TYPE]-YYYYMMDD-NNN
+

custom-skills/14-seo-core-web-vitals/desktop/skill.yaml

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+# Skill metadata (extracted from SKILL.md frontmatter)
+
+name: seo-core-web-vitals
+description: |
+  Core Web Vitals analyzer for LCP, FID, CLS, INP performance metrics. Triggers: Core Web Vitals, page speed, LCP, CLS, FID, INP, performance.
+
+# Optional fields
+allowed-tools:
+  - mcp__firecrawl__*
+  - mcp__perplexity__*
+
+# triggers: []  # TODO: Extract from description

custom-skills/14-seo-core-web-vitals/desktop/tools/firecrawl.md

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+# Firecrawl
+
+> TODO: Document tool usage for this skill
+
+## Available Commands
+
+- [ ] List commands
+
+## Configuration
+
+- [ ] Add configuration details
+
+## Examples
+
+- [ ] Add usage examples

custom-skills/14-seo-core-web-vitals/desktop/tools/perplexity.md

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+# Perplexity
+
+> TODO: Document tool usage for this skill
+
+## Available Commands
+
+- [ ] List commands
+
+## Configuration
+
+- [ ] Add configuration details
+
+## Examples
+
+- [ ] Add usage examples