claude-agent-service: cut memory request 2Gi → 1Gi (limit 4Gi → 2Gi)

Right-sizing per krr report (2026-05-22). Kept Burstable QoS (limit > request)
so an active agent run still has 2 GiB headroom — krr's 100 MiB recommendation
was measured idle and is not safe for an active job.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

stacks/claude-agent-service/main.tf

@@ -454,10 +454,10 @@ resource "kubernetes_deployment" "claude_agent" {
           resources {
             requests = {
               cpu    = "500m"
-              memory = "2Gi"
+              memory = "1Gi"
             }
             limits = {
-              memory = "4Gi"
+              memory = "2Gi"
             }
           }
         }