E-Mail PDF-Downloads als Binärdaten stabilisieren

KI-AGENT: Attachment-Downloads werden im Backend explizit als Buffer mit Content-Length ausgeliefert und im Frontend aus einem ArrayBuffer als Blob erzeugt, damit PDF-Anhänge unverändert gespeichert werden.

backend/src/modules/email/email.sync.service.ts

@@ -668,7 +668,9 @@ export function emailSyncService(server: FastifyInstance) {
                     return {
                         filename: attachment.filename || row.attachment.filename || "anhang",
                         contentType: attachment.contentType || row.attachment.contentType || "application/octet-stream",
-                        content: attachment.content,
+                        content: Buffer.isBuffer(attachment.content)
+                            ? attachment.content
+                            : Buffer.from(attachment.content),
                     }
                 }
             } finally {

backend/src/routes/emailAsUser.ts

@@ -466,9 +466,16 @@ export default async function emailAsUserRoutes(server: FastifyInstance) {
 
             if (!attachment) return reply.code(404).send({ error: "Anhang nicht gefunden" })
 
-            reply.header("Content-Type", attachment.contentType)
-            reply.header("Content-Disposition", `attachment; filename="${attachment.filename.replace(/"/g, "")}"`)
-            return reply.send(attachment.content)
+            const buffer = Buffer.isBuffer(attachment.content)
+                ? attachment.content
+                : Buffer.from(attachment.content)
+            const filename = attachment.filename.replace(/["\r\n]/g, "")
+
+            reply.header("Content-Type", attachment.contentType || "application/octet-stream")
+            reply.header("Content-Length", buffer.length)
+            reply.header("Cache-Control", "no-store")
+            reply.header("Content-Disposition", `attachment; filename="${filename}"`)
+            return reply.send(buffer)
         } catch (err: any) {
             req.log.error(err)
             return reply.code(500).send({ error: err.message || "Anhang konnte nicht geladen werden" })