Add published user products to the storefront sitemap.

Expose /sitemap-user-products.xml when customer_products is enabled, invalidate on listing mutations, and proxy the new path from nginx provision scripts.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/website-api/openapi.json

@@ -203,7 +203,7 @@
           "SEO"
         ],
         "summary": "XML sitemap for search engines",
-        "description": "Sitemap **index** for this tenant. Points to `/sitemap-main.xml` (static pages + product categories) plus module child sitemaps when enabled: `/sitemap-products.xml`, `/sitemap-blogs.xml`, `/sitemap-portfolios.xml`, `/sitemap-videos.xml`, `/sitemap-instructions.xml`, `/sitemap-workshops.xml`. Proxied from `https://{domain}/sitemap.xml`. Cached in Redis; refreshed after CMS writes and manifest sync.",
+        "description": "Sitemap **index** for this tenant. Points to `/sitemap-main.xml` (static pages + product categories) plus module child sitemaps when enabled: `/sitemap-products.xml`, `/sitemap-blogs.xml`, `/sitemap-portfolios.xml`, `/sitemap-videos.xml`, `/sitemap-instructions.xml`, `/sitemap-workshops.xml`, `/sitemap-user-products.xml` (when `customer_products` is enabled). Proxied from `https://{domain}/sitemap.xml`. Cached in Redis; refreshed after CMS writes and manifest sync.",
         "parameters": [
           {
             "$ref": "#/components/parameters/domain"
@@ -409,6 +409,32 @@
         }
       }
     },
+    "/tenants/{domain}/sitemap-user-products.xml": {
+      "get": {
+        "tags": [
+          "SEO"
+        ],
+        "summary": "User products sitemap urlset",
+        "description": "Published customer marketplace listings. Default paths: `/user-products/{slug}`. Included in the index when the `customer_products` module is enabled. Override path via sitemap-config `templates.userProduct`.",
+        "parameters": [
+          {
+            "$ref": "#/components/parameters/domain"
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "Sitemap XML (urlset) of published user products",
+            "content": {
+              "application/xml": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/tenants/{domain}/robots.txt": {
       "get": {
         "tags": [