Fix local-blocks processor: add traces_storage path

The local-blocks processor requires its own dedicated traces WAL
(traces_storage.path), separate from the ingester WAL and the
metrics generator WAL. Without it, the processor fails with
"local blocks processor requires traces wal".

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

argocd/manifests/tempo/tempo.yaml

@@ -34,6 +34,8 @@ metrics_generator:
     remote_write:
       - url: http://prometheus.monitoring.svc.cluster.local:9090/api/v1/write
         send_exemplars: true
+  traces_storage:
+    path: /var/tempo/generator/traces
   processor:
     span_metrics:
       dimensions: