right-size 14 services and scale down GPU-heavy workloads [ci skip]

Memory right-sizing based on VPA upperBound analysis:
- Increases: stirling-pdf 1200→1536Mi, claude-memory 64→128Mi,
  dawarich 512→768Mi, kyverno-cleanup 128→192Mi, linkwarden 768→1Gi,
  navidrome 64→128Mi, listenarr 768→896Mi, privatebin 64→128Mi,
  ntfy 64→128Mi, health 128→256Mi, dbaas quota 16→20Gi,
  mysql-operator 384→512Mi
- Decreases: rybbit 768→384Mi, nvidia-exporter added explicit 192Mi,
  dcgm-exporter 2560→1536Mi
- Scale to 0: ebook2audiobook/audiblez-web, whisper (GPU node pressure)

Net effect: -496Mi cluster-wide, 13 ContainerNearOOM alerts resolved,
all ResourceQuota pressures cleared, GPU health green.

stacks/platform/modules/nvidia/main.tf

@@ -132,7 +132,11 @@ resource "kubernetes_deployment" "nvidia-exporter" {
             }
           }
           resources {
+            requests = {
+              memory = "192Mi"
+            }
             limits = {
+              memory           = "192Mi"
               "nvidia.com/gpu" = "1"
             }
           }