fix: harden desktop monitoring recovery

server/internal/tenant/app/monitoring_phase2_desktop_tasks.go

@@ -225,12 +225,12 @@ func (s *MonitoringService) dispatchMonitorDesktopTasks(
 
 	repo := repository.NewDesktopTaskRepository(tx)
 	publishableTasks := make([]*repository.DesktopTask, 0, len(specs))
-	fallbackLegacyTaskIDs := make([]int64, 0)
+	deferredTaskIDs := make([]int64, 0)
 	for _, spec := range specs {
 		if spec.TargetAccountID == uuid.Nil || spec.TargetClientID == uuid.Nil {
 			target, ok := targets[normalizeMonitoringPlatformID(spec.PlatformID)]
 			if !ok || target.AccountID == uuid.Nil || target.ClientID == uuid.Nil {
-				fallbackLegacyTaskIDs = append(fallbackLegacyTaskIDs, spec.MonitorTaskID)
+				deferredTaskIDs = append(deferredTaskIDs, spec.MonitorTaskID)
 				continue
 			}
 			spec.TargetAccountID = target.AccountID
@@ -242,7 +242,7 @@ func (s *MonitoringService) dispatchMonitorDesktopTasks(
 			return nil, nil, upsertErr
 		}
 		if fallbackLegacy {
-			fallbackLegacyTaskIDs = append(fallbackLegacyTaskIDs, spec.MonitorTaskID)
+			deferredTaskIDs = append(deferredTaskIDs, spec.MonitorTaskID)
 			continue
 		}
 		if shouldPublish && task != nil {
@@ -250,10 +250,16 @@ func (s *MonitoringService) dispatchMonitorDesktopTasks(
 		}
 	}
 
+	if len(deferredTaskIDs) > 0 {
+		if err := deferPhase2MonitorCollectTasks(ctx, tx, deferredTaskIDs, defaultMonitoringDailyDesktopRetryCooldown); err != nil {
+			return nil, nil, err
+		}
+	}
+
 	if err := tx.Commit(ctx); err != nil {
 		return nil, nil, response.ErrInternal(50116, "desktop_task_commit_failed", "failed to commit phase2 monitor desktop dispatch")
 	}
-	return publishableTasks, fallbackLegacyTaskIDs, nil
+	return publishableTasks, deferredTaskIDs, nil
 }
 
 func monitorDesktopTaskSpecsNeedTargetLookup(specs []monitorDesktopTaskSpec) bool {
@@ -738,6 +744,35 @@ func (s *MonitoringService) fallbackMonitorDesktopTasksToLegacy(ctx context.Cont
 	return nil
 }
 
+func deferPhase2MonitorCollectTasks(ctx context.Context, tx pgx.Tx, taskIDs []int64, delay time.Duration) error {
+	if tx == nil || len(taskIDs) == 0 {
+		return nil
+	}
+	if delay <= 0 {
+		delay = defaultMonitoringDailyDesktopRetryCooldown
+	}
+	if _, err := tx.Exec(ctx, `
+		UPDATE monitoring_collect_tasks
+		SET status = 'pending',
+		    lease_token_hash = NULL,
+		    leased_to_executor = NULL,
+		    leased_at = NULL,
+		    lease_expires_at = NULL,
+		    callback_received_at = NULL,
+		    completed_at = NULL,
+		    skip_reason = NULL,
+		    dispatch_after = NOW() + $2::interval,
+		    error_message = NULL,
+		    updated_at = NOW()
+		WHERE id = ANY($1::bigint[])
+		  AND COALESCE(execution_owner, 'legacy') = 'desktop_tasks'
+		  AND callback_received_at IS NULL
+	`, uniqueInt64s(taskIDs), formatPgInterval(delay)); err != nil {
+		return response.ErrInternal(50041, "task_defer_failed", "failed to defer phase2 monitor tasks until a desktop client is online")
+	}
+	return nil
+}
+
 func (s *MonitoringService) deferQueuedPhase2MonitorTasks(
 	ctx context.Context,
 	targetClientID uuid.UUID,