feat(commerce/seo): add descriptionSource option to SeoPDPV2

Adds a `descriptionSource` prop ("seo" | "product") that controls which
field is used as the meta description when no manual override is set.

- "seo" (default): uses jsonLD.seo.description — existing behavior, no breaking change
- "product": strips HTML from jsonLD.product.description — useful when
  the SEO description is empty or when the richer product copy is preferred

In VTEX, product.description is a rich-text HTML field meant for page
display, while seo.description maps to metaTagDescription — a plain-text
field designed for meta tags. The "product" source strips HTML before
writing to <meta name="description"> and og:description.

Falls back to the other source if the chosen one is empty.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: igoramf

commerce/sections/Seo/SeoPDPV2.tsx

@@ -15,6 +15,13 @@ export interface Props {
   title?: string;
   /** @title Description Override */
   description?: string;
+  /**
+   * @title Description Source
+   * @description Choose which field to use as the meta description when no Description Override is set.
+   * "seo" uses the SEO description from the search index (default).
+   * "product" uses the product's own description field, stripping HTML tags — useful when the SEO description is empty or you prefer the richer product copy.
+   */
+  descriptionSource?: "seo" | "product";
   /**
    * @title Disable indexing
    * @description In testing, you can use this to prevent search engines from indexing your site
@@ -38,18 +45,30 @@ export function loader(_props: Props, _req: Request, ctx: AppContext) {
   const {
     title: titleProp,
     description: descriptionProp,
+    descriptionSource = "seo",
     jsonLD,
     omitVariants,
     ignoreStructuredData,
   } = props;
 
+  const productDescription = jsonLD?.product.description
+    ?.replace(/<[^>]+>/g, " ")
+    .replace(/\s+/g, " ")
+    .trim();
+
+  const resolvedDescription = descriptionProp ||
+    (descriptionSource === "product"
+      ? productDescription || jsonLD?.seo?.description
+      : jsonLD?.seo?.description || productDescription) ||
+    ctx.seo?.description || "";
+
   const title = renderTemplateString(
     titleTemplate,
     titleProp || jsonLD?.seo?.title || ctx.seo?.title || "",
   );
   const description = renderTemplateString(
     descriptionTemplate,
-    descriptionProp || jsonLD?.seo?.description || ctx.seo?.description || "",
+    resolvedDescription,
   );
   const image = jsonLD?.product.image?.[0]?.url;
   const canonical = jsonLD?.seo?.canonical