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

src/lib/llm/synthesize.ts

@@ -64,13 +64,29 @@ export async function synthesizePending(limit: number = 24) {
 
   let ok = 0;
   let failed = 0;
+  // Dead-letter: a row that is still `fetched` after 24h of continuous
+  // failure will never succeed on its own (poison content, oversized
+  // source, provider rejection). Mark it `failed` so it stops consuming
+  // a slot in every cron pass and out of the backlog. Manual re-queue by
+  // resetting status to `fetched` if the cause is later fixed.
+  const deadAfter = new Date(Date.now() - 24 * 60 * 60 * 1000);
   for (const a of pending) {
     try {
       await synthesizeArticle(a.id);
       ok += 1;
     } catch (err) {
       failed += 1;
-      console.error(`[synth] failed article ${a.slug}:`, (err as Error).message);
+      const dead = a.createdAt < deadAfter;
+      const why = (err as Error).message;
+      if (dead) {
+        await prisma.article.update({
+          where: { id: a.id },
+          data: { status: 'failed' },
+        });
+        console.error(`[synth] DEAD-LETTER ${a.slug} (failed >24h): ${why}`);
+      } else {
+        console.error(`[synth] failed article ${a.slug}: ${why}`);
+      }
     }
   }
   return { total: pending.length, ok, failed };