feat: save insurance PDFs (eligibility/claims/preauth) to Cloud Storage instead of Postgres blobs

New saves go into the patient's Cloud Storage folder under category subfolders
(Eligibility/Claims/PreAuth/Claim Status/Attachments) via a new
storage.savePdfToCloudStorage helper, instead of the legacy PdfGroup/PdfFile
Postgres blob tables. Old records and their read paths are left untouched for
backward compatibility; PDF list/content/delete endpoints and viewers now
transparently handle both legacy numeric ids and new "cloud:<id>" ids.

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

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

@@ -143,6 +143,24 @@ export interface IStorage {
     patientId: number,
     patientName: string
   ): Promise<CloudFolder>;
+  getOrCreateSubfolder(
+    userId: number,
+    parentId: number,
+    name: string
+  ): Promise<CloudFolder>;
+  savePdfToCloudStorage(
+    userId: number,
+    patientId: number,
+    patientName: string,
+    category: "Eligibility" | "Claims" | "PreAuth" | "Claim Status" | "Attachments",
+    filename: string,
+    buffer: Buffer,
+    mimeType?: string
+  ): Promise<CloudFile>;
+  listPatientCategoryCloudFiles(
+    patientId: number,
+    category: string
+  ): Promise<CloudFile[]>;
 }
 
 /* ------------------------------- Implementation ------------------------------- */
@@ -546,6 +564,82 @@ export const cloudStorageStorage: IStorage = {
     return created as unknown as CloudFolder;
   },
 
+  async getOrCreateSubfolder(userId: number, parentId: number, name: string) {
+    const existing = await db.cloudFolder.findFirst({
+      where: { parentId, name },
+    });
+    if (existing) return existing as unknown as CloudFolder;
+
+    try {
+      return await cloudStorageStorage.createFolder(userId, name, parentId);
+    } catch (err: any) {
+      // unique constraint on [userId, parentId, name] - another request created it first
+      if (err?.code === "P2002") {
+        const race = await db.cloudFolder.findFirst({ where: { parentId, name } });
+        if (race) return race as unknown as CloudFolder;
+      }
+      throw err;
+    }
+  },
+
+  async savePdfToCloudStorage(
+    userId: number,
+    patientId: number,
+    patientName: string,
+    category: "Eligibility" | "Claims" | "PreAuth" | "Claim Status" | "Attachments",
+    filename: string,
+    buffer: Buffer,
+    mimeType: string = "application/pdf"
+  ) {
+    const patientFolder = await cloudStorageStorage.getOrCreatePatientFolder(
+      userId,
+      patientId,
+      patientName
+    );
+    const subfolder = await cloudStorageStorage.getOrCreateSubfolder(
+      userId,
+      patientFolder.id!,
+      category
+    );
+    const cloudFile = await cloudStorageStorage.initializeFileUpload(
+      userId,
+      filename,
+      mimeType,
+      BigInt(buffer.length),
+      1,
+      subfolder.id!
+    );
+    await cloudStorageStorage.appendFileChunk(cloudFile.id!, 0, buffer);
+    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");
+    return finalFile;
+  },
+
+  async listPatientCategoryCloudFiles(patientId: number, category: string) {
+    const patientFolder = await db.cloudFolder.findFirst({ where: { patientId } });
+    if (!patientFolder) return [];
+    const subfolder = await db.cloudFolder.findFirst({
+      where: { parentId: patientFolder.id, name: category },
+    });
+    if (!subfolder) return [];
+    const files = await db.cloudFile.findMany({
+      where: { folderId: subfolder.id, isComplete: true },
+      orderBy: { createdAt: "desc" },
+      select: {
+        id: true,
+        name: true,
+        mimeType: true,
+        fileSize: true,
+        folderId: true,
+        isComplete: true,
+        createdAt: true,
+        updatedAt: true,
+      },
+    });
+    return files.map(serializeFile) as unknown as CloudFile[];
+  },
+
   // --- STREAM ---
   async streamFileTo(resStream: NodeJS.WritableStream, fileId: number) {
     const file = await db.cloudFile.findUnique({