[ci skip] fix post-NFS-migration issues: MySQL GR, Loki, grampsweb, alerts

- Loki: reduce memory limit from 6Gi to 4Gi (within LimitRange max)
- Grampsweb: increase memory to 2Gi (was OOMKilled at 512Mi)
- Fix PostgreSQLDown alert: check pod readiness instead of deployment
- Fix MySQLDown alert: check StatefulSet replicas instead of deployment
- Fix RedisDown alert: check StatefulSet replicas instead of deployment
- Fix NFSServerUnresponsive: aggregate all NFS versions cluster-wide
- Fix Uptime Kuma healthcheck: handle nested list heartbeat format
- Update etcd backup image to registry.k8s.io/etcd:3.6.5-0

stacks/grampsweb/main.tf

@@ -186,11 +186,11 @@ resource "kubernetes_deployment" "grampsweb" {
           resources {
             requests = {
               cpu    = "50m"
-              memory = "256Mi"
+              memory = "512Mi"
             }
             limits = {
-              cpu    = "500m"
-              memory = "512Mi"
+              cpu    = "1"
+              memory = "2Gi"
             }
           }
         }
@@ -256,7 +256,7 @@ resource "kubernetes_deployment" "grampsweb" {
             }
             limits = {
               cpu    = "500m"
-              memory = "512Mi"
+              memory = "1Gi"
             }
           }
         }