PERF(observability): remove CPU limits for stability

- Remove CPU limits from all observability components
- Prevents CPU throttling issues across monitoring stack

thanos/helm-values.yaml

@@ -46,13 +46,12 @@ query:
     - --query.replica-label=prometheus_replica
     - --query.auto-downsampling
 
-  # Resource settings (VPA lowerBound/target)
+  # Resource settings (no CPU limit for stability)
   resources:
     requests:
       cpu: 15m
       memory: 100Mi
     limits:
-      cpu: 15m
       memory: 126Mi
 
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