feat(scan): support iX1600 duplex scanning on Linux

backend/src/routes/instanceAgentGateway.ts

@@ -1,7 +1,8 @@
 import { FastifyInstance, FastifyRequest } from "fastify"
 import multipart from "@fastify/multipart"
 import { createHash } from "node:crypto"
-import { and, asc, eq, sql } from "drizzle-orm"
+import { basename } from "node:path"
+import { and, asc, eq, inArray, sql } from "drizzle-orm"
 import { instanceAgentScanJobs, instanceAgents } from "../../db/schema"
 import { saveFile } from "../utils/files"
 
@@ -178,11 +179,12 @@ export default async function instanceAgentGatewayRoutes(server: FastifyInstance
             })
             .where(and(
                 eq(instanceAgentScanJobs.id, req.params.id),
-                eq(instanceAgentScanJobs.agentId, agent.id)
+                eq(instanceAgentScanJobs.agentId, agent.id),
+                inArray(instanceAgentScanJobs.status, ["pending", "running"])
             ))
             .returning()
 
-        if (!job) return reply.code(404).send({ error: "Scan job not found" })
+        if (!job) return reply.code(409).send({ error: "Scan job is no longer active or does not exist" })
 
         return { job }
     })
@@ -209,7 +211,8 @@ export default async function instanceAgentGatewayRoutes(server: FastifyInstance
         if (!data?.file) return reply.code(400).send({ error: "No file uploaded" })
 
         const fileBuffer = await data.toBuffer()
-        const filename = job.requestedFilename || data.filename || `${job.id}.pdf`
+        // The agent normalizes the extension to the actual output format.
+        const filename = basename(data.filename || job.requestedFilename || `${job.id}.pdf`)
 
         const createdFile = await saveFile(
             server,