btg: paragraphJson fix

scripts/seed-magazines.ts

@@ -107,25 +107,35 @@ async function seedOneMagazine(
       const rawParas = (issue.paragraphs as string[]) || [];
       const cleanParas = rawParas.map((p: string) => sanitizeString(String(p)));
 
-      // Store paragraphs as a single JSON string to avoid MongoDB BSON
-      // wire protocol issues with large string arrays.
-      // The data layer will JSON.parse() this back into an array on read.
-      const paragraphsJson = JSON.stringify(cleanParas);
-
-      const doc = {
+      // Insert the base document without paragraphs first, then $set paragraphs.
+      // This avoids the MongoDB BSON wire protocol "Not null terminated string"
+      // error that occurs with large string arrays in insertOne/replaceOne.
+      const baseDoc = {
         book: bookCode,
         volume: issue.volume,
         part: issue.part,
         title: issue.title,
         slug: issue.slug,
         order: issue.order,
-        paragraphsJson,
-        paragraphs: [] as string[], // Keep empty array for schema compat
+        paragraphs: [] as string[],
       };
 
-      await issuesCol.replaceOne({ book: bookCode, slug: issue.slug }, doc, {
-        upsert: true,
-      });
+      await issuesCol.replaceOne(
+        { book: bookCode, slug: issue.slug as string },
+        baseDoc,
+        { upsert: true },
+      );
+
+      // Now set paragraphs in batches using $push to avoid BSON limits
+      const BATCH_SIZE = 200;
+      for (let bi = 0; bi < cleanParas.length; bi += BATCH_SIZE) {
+        const batch = cleanParas.slice(bi, bi + BATCH_SIZE);
+        await issuesCol.updateOne(
+          { book: bookCode, slug: issue.slug as string },
+          { $push: { paragraphs: { $each: batch } } },
+        );
+      }
+
       inserted++;
     }
     console.log(`  📄 Issues: ${inserted}`);