articles: strip dead WP image tags from imported post bodies

rewriteLegacyImageUrlsInHtml only swapped URLs that had a mapping in
legacy-image-map.json — anything missing the map was left pointing at
the dead https://www.broadcastbeat.com/wp-content/uploads/ host (404
in browsers, bad for SEO, broken-image icons everywhere).

New stripDeadLegacyImages() pass runs after the rewrite and removes:
- <figure> blocks whose only inner image is a dead WP image
- <a> wrappers around dead images
- Bare <img dead> tags
- Empty <figure> leftovers
…leaving body copy intact and figcaption-less.

cleanLegacyImages() is the one-call helper that pipes both steps.
Applied via rowToArticle so every /news/<slug> render gets it.

src/lib/articles/legacy-source.ts

@@ -1,6 +1,6 @@
 import { createClient } from "@supabase/supabase-js";
 import type { Article } from "./types";
-import { rewriteLegacyImageUrl, rewriteLegacyImageUrlsInHtml } from "@/lib/legacy-image";
+import { rewriteLegacyImageUrl, cleanLegacyImages } from "@/lib/legacy-image";
 
 const SUPABASE_URL = process.env.NEXT_PUBLIC_SUPABASE_URL!;
 const SUPABASE_ANON = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!;
@@ -128,7 +128,7 @@ function rowToArticle(row: ImportedPostRow, section: Section = "news"): Article
   const image = row.featured_image
     ? rewriteLegacyImageUrl(row.featured_image)
     : FALLBACK_IMAGE;
-  const content = rewriteLegacyImageUrlsInHtml(row.content || "");
+  const content = cleanLegacyImages(row.content || "");
   const author = row.author_name || "Broadcast Beat";
   return {
     slug: row.wp_slug,