Prevent tenant merge dry-run memory spikes

backend/src/routes/admin.ts

@@ -401,6 +401,12 @@ export default async function adminRoutes(server: FastifyInstance) {
         contentType: string,
         filename: string
     ) => {
+        const heartbeat = setInterval(() => {
+            void server.db
+                .update(tenantExportJobs)
+                .set({ updatedAt: new Date() })
+                .where(eq(tenantExportJobs.id, jobId));
+        }, 15_000);
         try {
             const exportData = await parseMergeSource(source, contentType, filename);
             const report = sanitizeTenantMergePlan(await createTenantMergeDryRun(exportData, targetTenantId));
@@ -434,6 +440,8 @@ export default async function adminRoutes(server: FastifyInstance) {
                     updatedAt: new Date(),
                 })
                 .where(eq(tenantExportJobs.id, jobId));
+        } finally {
+            clearInterval(heartbeat);
         }
     };
 
@@ -1466,11 +1474,25 @@ export default async function adminRoutes(server: FastifyInstance) {
 
             if (!job) return reply.code(404).send({ error: "Export not found" });
 
+            let returnedStatus = job.status;
+            const staleMergeReview = job.operation === "merge"
+                && ["running", "recovering"].includes(job.status)
+                && (!job.updatedAt || Date.now() - new Date(job.updatedAt).getTime() > 60_000);
+            if (staleMergeReview && job.storagePath) {
+                const source = await readS3Buffer(job.storagePath);
+                await server.db
+                    .update(tenantExportJobs)
+                    .set({ status: "recovering", updatedAt: new Date(), error: null })
+                    .where(eq(tenantExportJobs.id, job.id));
+                void startTenantMergeReviewJob(job.id, job.tenantId, source, job.contentType, job.filename);
+                returnedStatus = "recovering";
+            }
+
             return {
                 exportId: job.id,
                 tenantId: job.tenantId,
                 operation: job.operation,
-                status: job.status,
+                status: returnedStatus,
                 filename: job.filename,
                 fileSize: job.fileSize,
                 filesDone: job.filesDone,