right-size memory requests to unblock GPU workloads and fix dbaas quota [ci skip]

- nvidia: custom LimitRange (128Mi default, was 1Gi from Kyverno) to stop
  inflating GPU operator init containers; saves ~2.5Gi on GPU node
- nvidia: dcgm-exporter 1536Mi → 768Mi (actual usage 489Mi)
- monitoring: prometheus server 4Gi → 3Gi (actual usage 2.6Gi)
- onlyoffice: 2304Mi → 1536Mi (actual usage 1.3Gi)
- immich: frame explicit 64Mi resources (was getting 1Gi LimitRange default)
- dbaas: quota limits.memory 20Gi → 24Gi to fit 3rd MySQL replica

Root cause: Kyverno tier-2-gpu LimitRange injected 1Gi on every NVIDIA init
container (no explicit resources), wasting ~2.5Gi scheduling overhead on the
GPU node. Combined with over-requesting, frigate and immich-ml couldn't schedule.

stacks/onlyoffice/main.tf

@@ -134,10 +134,10 @@ resource "kubernetes_deployment" "onlyoffice-document-server" {
           resources {
             requests = {
               cpu    = "100m"
-              memory = "2304Mi"
+              memory = "1536Mi"
             }
             limits = {
-              memory = "2304Mi"
+              memory = "1536Mi"
             }
           }
           port {