fix: two bugs in Cloud Storage PDF viewing surfaced by live testing

- PDF viewer hung on "Loading" forever for cloud-backed PDFs: streamFileTo
  pipes with {end: false} (by design, so cloud-storage.ts's own routes can
  call res.end() themselves), but the new /pdf-files/:id cloud branch never
  did, so the HTTP response never completed.
- Documents page showed nothing for patients whose PDFs are only in Cloud
  Storage: the page lists categories from the legacy PdfGroup table, which
  new saves stopped populating. savePdfToCloudStorage now also ensures a
  blob-less PdfGroup row exists per patient/category so the category still
  appears, with actual files served from Cloud Storage via the existing
  merge in the pdf-files/group listing routes.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/Backend/src/routes/documents.ts

@@ -290,9 +290,11 @@ router.get(
         );
         try {
           await storage.streamFileTo(res, cloudId);
+          if (!res.writableEnded) res.end();
         } catch (streamErr) {
           console.error("Error streaming cloud PDF file:", streamErr);
           if (!res.headersSent) res.status(500).json({ error: "Failed to stream PDF" });
+          else if (!res.writableEnded) res.end();
         }
         return;
       }

apps/Backend/src/storage/cloudStorage-storage.ts

@@ -613,6 +613,29 @@ export const cloudStorageStorage: IStorage = {
     await cloudStorageStorage.finalizeFileUpload(cloudFile.id!);
     const finalFile = await cloudStorageStorage.getFile(cloudFile.id!);
     if (!finalFile) throw new Error("Failed to finalize PDF upload to cloud storage");
+
+    // Ensure a (blob-less) PdfGroup row exists for this patient/category so the
+    // Documents page — which lists categories from PdfGroup — still shows this
+    // category even when every PDF in it lives in Cloud Storage.
+    const CATEGORY_TO_TITLE_KEY: Record<string, { titleKey: string; title: string }> = {
+      Eligibility: { titleKey: "ELIGIBILITY_STATUS", title: "Eligibility Status" },
+      Claims: { titleKey: "INSURANCE_CLAIM", title: "Claims" },
+      PreAuth: { titleKey: "INSURANCE_CLAIM_PREAUTH", title: "Preauth" },
+      "Claim Status": { titleKey: "CLAIM_STATUS", title: "Claim Status" },
+      Attachments: { titleKey: "OTHER", title: "Attachments" },
+    };
+    const mapping = CATEGORY_TO_TITLE_KEY[category];
+    if (mapping) {
+      const existingGroup = await db.pdfGroup.findFirst({
+        where: { patientId, titleKey: mapping.titleKey as any },
+      });
+      if (!existingGroup) {
+        await db.pdfGroup.create({
+          data: { patientId, title: mapping.title, titleKey: mapping.titleKey as any },
+        });
+      }
+    }
+
     return finalFile;
   },