CHORE(app): reduce resource limits

- CPU limit: 300m → 50m (prod), 210m → 30m (dev)
- Memory limit: 230Mi → 120Mi (prod), 161Mi → 100Mi (dev)
- ResourceQuota adjusted accordingly

Actual usage: ~3m CPU, ~71Mi memory

deploy/k8s/overlays/prod/resourcequota.yaml

@@ -5,9 +5,9 @@ metadata:
   namespace: todo
 spec:
   hard:
-    requests.memory: "750Mi"
-    requests.cpu: "600m"
-    limits.memory: "1200Mi"
-    limits.cpu: "1200m"
+    requests.memory: "250Mi"
+    requests.cpu: "100m"
+    limits.memory: "500Mi"
+    limits.cpu: "200m"
     pods: "9"