FEAT(observability): enable HA with replica 2 and soft anti-affinity

- Add replicaCount: 2 to goldilocks, vpa, alertmanager
- Add replicas: 2 to loki singleBinary
- Add soft pod anti-affinity for node distribution
- Keep kube-state-metrics at replica 1 to prevent duplicate metrics

FIX(loki): revert to replica 1 for Single Binary mode

- Single Binary mode cannot run more than 1 replica without object storage
- Remove affinity configuration for single replica
- Keep filesystem storage backend

kube-state-metrics/helm-values.yaml

@@ -3,6 +3,10 @@
 
 fullnameOverride: kube-state-metrics
 
+# replicaCount: 1 (default)
+# Note: kube-state-metrics는 stateless이지만, 여러 replica는 동일한 메트릭을 중복 생성하므로
+# 단일 replica로 실행하는 것이 권장됩니다.
+
 resources:
   requests:
     cpu: 15m