fix(pipeline): dedupe+P2002; add red maple-leaf cover system; replace dead CBC feeds (Google News CN / NatPost Canada); worker dead-letter

src/app/article/[slug]/page.tsx

@@ -4,6 +4,7 @@ import { notFound } from 'next/navigation';
 import { getArticleFull, getRelatedArticles } from '@/lib/queries';
 import RelatedArticles from '@/components/RelatedArticles';
 import { InArticleAd, SidebarAd } from '@/components/ads/placements';
+import { categoryCover, resolveCoverImage } from '@/lib/cover';
 import { env } from '@/lib/env';
 import { formatFull } from '@/lib/format';
 import { safeParse } from '@/lib/llm/parse';
@@ -56,15 +57,18 @@ export async function generateMetadata({
       modifiedTime: a.synthesizedAt?.toISOString(),
       section: sectionLabel,
       tags: a.tags ? safeParse<string[]>(a.tags).slice(0, 5) : undefined,
-      images: a.image
-        ? [{ url: a.image, width: 1200, height: 630, alt: title }]
-        : [{ url: '/og-image.png', width: 1200, height: 630, alt: 'MapleBrief' }],
+      images: [{
+        url: (a.image && a.image.trim()) || categoryCover(a.category),
+        width: 1200,
+        height: 630,
+        alt: title,
+      }],
     },
     twitter: {
       card: 'summary_large_image',
       title,
       description,
-      images: a.image ? [a.image] : undefined,
+      images: [(a.image && a.image.trim()) || categoryCover(a.category)],
     },
   };
 }
@@ -102,14 +106,11 @@ export default async function ArticlePage({
             </h1>
           </header>
 
-          {a.image && (
-            // eslint-disable-next-line @next/next/no-img-element
-            <img
-              src={a.image}
-              alt={title}
-              className="mt-6 aspect-[16/8] w-full rounded-2xl object-cover"
-            />
-          )}
+          <img
+            src={resolveCoverImage(a.image, a.category)}
+            alt={title}
+            className="mt-6 aspect-[16/8] w-full rounded-2xl object-cover"
+          />
 
           {takeaways.length > 0 && (
             <section className="mt-8 rounded-xl border-l-4 border-maple-600 bg-maple-50 p-5">