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)

package.json

@@ -4,6 +4,8 @@
   "private": true,
   "scripts": {
     "dev": "next dev",
+    "generate:integrations": "npx tsx scripts/generate-integrations.ts",
+    "prebuild": "npm run generate:integrations",
     "build": "next build --webpack",
     "start": "next start",
     "lint": "next lint",
@@ -37,18 +39,21 @@
     "d3-array": "^3.2.4",
     "d3-scale": "^4.0.2",
     "framer-motion": "^12.23.26",
+    "gray-matter": "^4.0.3",
     "html-to-image": "^1.11.13",
     "iso-3166-2": "^1.0.0",
     "jspdf": "^4.0.0",
     "jspdf-autotable": "^5.0.7",
     "lucide-react": "^0.577.0",
     "next": "^16.1.1",
+    "next-mdx-remote": "^6.0.0",
     "radix-ui": "^1.4.3",
     "react": "^19.2.3",
     "react-dom": "^19.2.3",
     "react-markdown": "^10.1.0",
     "react-use-measure": "^2.1.7",
     "recharts": "^2.15.0",
+    "remark-gfm": "^4.0.1",
     "sonner": "^2.0.7",
     "svg-dotted-map": "^2.0.1",
     "swr": "^2.3.3",