Enable local-blocks processor for Grafana Traces Drilldown

Required by Grafana's TraceQL metrics queries. Keeps recent
traces in memory for query-time aggregation without
duplicating data to storage.

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

argocd/manifests/tempo/tempo.yaml

@@ -44,6 +44,8 @@ metrics_generator:
     service_graphs:
       dimensions:
         - service.name
+    local_blocks:
+      flush_to_storage: false
 
 overrides:
   defaults:
@@ -51,3 +53,4 @@ overrides:
       processors:
         - span-metrics
         - service-graphs
+        - local-blocks