fix: increase memory limits for OOMKilled pods (immich, clickhouse, speedtest)

- immich-server: limits 1700Mi → 2500Mi (70 restarts from media processing spikes)
- clickhouse: limits 1Gi → 1536Mi, max_server_memory_usage 800Mi → 1200Mi
- speedtest: limits 256Mi → 512Mi, requests 256Mi → 128Mi (daily OOM during test)

stacks/immich/main.tf

@@ -287,7 +287,7 @@ resource "kubernetes_deployment" "immich_server" {
               memory = "1700Mi"
             }
             limits = {
-              memory = "1700Mi"
+              memory = "2500Mi"
             }
           }
         }