feat: trim integration pages from 75 to 25 + migrate to MDX

- Add dedicatedPage flag to integration registry (25 true, 50 false)
- Delete hardcoded nextjs/react/vue/wordpress route pages (wrong metadata)
- Hub page routes non-dedicated integrations to /integrations/script-tag
- Add 301 redirects for 50 removed slugs → /integrations/script-tag
- Migrate guide content from TSX to MDX (content/integrations/*.mdx)
- Add gray-matter, next-mdx-remote, remark-gfm dependencies
- Add content loader (lib/integration-content.ts) matching ciphera-website pattern
- Add prebuild script for integration guide index generation
- Sitemap reduced from 83 to 35 URLs with real lastmod dates
- Remove seoDescription from registry (now in MDX frontmatter)

app/sitemap.ts

@@ -1,9 +1,13 @@
 import type { MetadataRoute } from 'next'
 import { integrations } from '@/lib/integrations'
+import { getIntegrationGuides } from '@/lib/integration-content'
 
 const BASE_URL = 'https://pulse.ciphera.net'
 
 export default function sitemap(): MetadataRoute.Sitemap {
+  const guides = getIntegrationGuides()
+  const guidesBySlug = new Map(guides.map((g) => [g.slug, g]))
+
   const publicRoutes = [
     { url: '', priority: 1.0, changeFrequency: 'weekly' as const },
     { url: '/about', priority: 0.8, changeFrequency: 'monthly' as const },
@@ -13,20 +17,33 @@ export default function sitemap(): MetadataRoute.Sitemap {
     { url: '/changelog', priority: 0.6, changeFrequency: 'weekly' as const },
     { url: '/installation', priority: 0.8, changeFrequency: 'monthly' as const },
     { url: '/integrations', priority: 0.8, changeFrequency: 'monthly' as const },
+    { url: '/integrations/script-tag', priority: 0.6, changeFrequency: 'monthly' as const },
   ]
 
-  const integrationRoutes = integrations.map((i) => ({
-    url: `/integrations/${i.id}`,
-    priority: 0.7,
-    changeFrequency: 'monthly' as const,
-  }))
+  const integrationRoutes = integrations
+    .filter((i) => i.dedicatedPage)
+    .map((i) => {
+      const guide = guidesBySlug.get(i.id)
+      return {
+        url: `/integrations/${i.id}`,
+        priority: 0.7,
+        changeFrequency: 'monthly' as const,
+        lastModified: guide?.date ? new Date(guide.date) : new Date('2026-03-28'),
+      }
+    })
 
-  const allRoutes = [...publicRoutes, ...integrationRoutes]
-
-  return allRoutes.map((route) => ({
-    url: `${BASE_URL}${route.url}`,
-    lastModified: new Date(),
-    changeFrequency: route.changeFrequency,
-    priority: route.priority,
-  }))
+  return [
+    ...publicRoutes.map((route) => ({
+      url: `${BASE_URL}${route.url}`,
+      lastModified: new Date('2026-03-28'),
+      changeFrequency: route.changeFrequency,
+      priority: route.priority,
+    })),
+    ...integrationRoutes.map((route) => ({
+      url: `${BASE_URL}${route.url}`,
+      lastModified: route.lastModified,
+      changeFrequency: route.changeFrequency,
+      priority: route.priority,
+    })),
+  ]
 }