feat: Add relations JSON to llms.txt and per-product sitemaps

- Add Class Relationship Graphs section to main llms.txt explaining
  the relations JSON format and what data it contains
- Add relations JSON, hooks JSON, and llms.txt URLs to each product's
  sitemap for better discoverability by crawlers and AI agents

Author: zackkatz

scripts/enhance-for-llms.mjs

@@ -546,9 +546,21 @@ ${urlStructureSection}
 
 ## Machine-Readable Data
 
-For programmatic access to hook information:
+For programmatic access to hook information and code structure:
 
-### Recommended: Per-Product APIs (Smaller Files)
+### Class Relationship Graphs (For Code Understanding)
+- \`/relations/{product-id}.json\` - Class inheritance, traits, dependencies, and call graphs
+
+These relationship files enable AI assistants to understand codebase architecture without direct code access. Each file contains:
+- **extends** - Parent class inheritance
+- **implements** - Interface implementations
+- **uses** - Trait usage
+- **dependencies** - Constructor/method type-hinted dependencies
+- **instantiates** - Classes created via \`new\`
+- **staticCalls** - Static method calls to other classes
+- **usedBy** - Reverse lookup (what uses this class)
+
+### Hooks APIs (For WordPress Integration)
 - \`/api/hooks/index.json\` - Product directory with stats (~6KB)
 - \`/api/hooks/{product-id}.json\` - Individual product hooks (1KB-408KB each)
 

src/plugins/product-sitemaps.mjs

@@ -129,6 +129,31 @@ export default function productSitemapsPlugin(context, options) {
           };
         });
 
+        // Add machine-readable API files to sitemap
+        // Relations JSON (class relationships for code understanding)
+        sitemapItems.push({
+          url: normalizeUrl([baseUrl, 'relations', `${productId}.json`]),
+          lastmod: new Date().toISOString().split('T')[0],
+          changefreq: 'weekly',
+          priority: 0.8,
+        });
+
+        // Hooks JSON (WordPress hooks API)
+        sitemapItems.push({
+          url: normalizeUrl([baseUrl, 'api', 'hooks', `${productId}.json`]),
+          lastmod: new Date().toISOString().split('T')[0],
+          changefreq: 'weekly',
+          priority: 0.8,
+        });
+
+        // Product-specific llms.txt
+        sitemapItems.push({
+          url: normalizeUrl([baseUrl, 'docs', productId, 'llms.txt']),
+          lastmod: new Date().toISOString().split('T')[0],
+          changefreq: 'weekly',
+          priority: 0.8,
+        });
+
         // Generate sitemap XML
         const sitemapXML = generateSitemapXML(sitemapItems, productLabel);