CHORE(app): reduce memory to 100Mi

- Memory limit: 200Mi -> 100Mi
- Memory request: 100Mi -> 50Mi
- Current usage is only ~36Mi, so 100Mi limit is sufficient

deploy/k8s/overlays/prod/deployment-patch.yaml

@@ -12,8 +12,8 @@ spec:
         - name: portfolio-app
           resources:
             requests:
-              memory: "100Mi"
+              memory: "50Mi"
               cpu: "50m"
             limits:
-              memory: "200Mi"
+              memory: "100Mi"
               cpu: "150m"