SEO-friendly id-based URLs, sitemap/robots, and homepage category banners

- Replace legacy DB-slug URLs with /products/{id}/{fa-slug},
  /products/category/{id}/{fa-slug}, and /blog/{id}/{fa-slug}, backed by
  the new by-id API endpoints and a Persian slugify helper
- Add /sitemap.xml (index) + /sitemap-main.xml + /sitemap-products.xml
  and /robots.txt pointing to it
- Register the three-banner-row slot in the static-image-slots catalog
- Replace the homepage category carousel with a 3-column linkable
  ThreeBanners section wired to that slot
- Remove the now-superseded root prompt files (moved into Ai data/)

.gitignore

@@ -2,6 +2,8 @@
 
 # dependencies
 /node_modules
+/ai-data
+/psd
 /.pnp
 .pnp.*
 .yarn/*