fix OOMKilled containers: bump immich/actualbudget memory, disable changedetection, cap clickhouse

- immich-server: 512Mi/1Gi → 1700Mi/1700Mi (VPA upperBound 1.39Gi, 34 OOM restarts)
- actualbudget http-api: 384Mi → 768Mi (VPA upperBound 615Mi, 3 OOM restarts)
- changedetection: replicas 1 → 0 (chronic OOM at 64Mi, not worth memory cost)
- rybbit clickhouse: add ConfigMap capping max_server_memory_usage to 800Mi (within 1Gi limit)

stacks/changedetection/main.tf

@@ -76,7 +76,8 @@ resource "kubernetes_deployment" "changedetection" {
     }
   }
   spec {
-    replicas = 1
+    # Disabled: chronic OOM at 64Mi limit, not worth the memory cost to increase
+    replicas = 0
     strategy {
       type = "Recreate"
     }