feat: Add Kustomize environment configurations for dev, staging, and prod deployments

- Add dev kustomization with debug logging, 100 req/min rate limit, single replica counts
- Add staging kustomization with info logging, 500 req/min rate limit, 2 replicas, metrics enabled
- Add prod kustomization with warn logging, 1000 req/min rate limit, 2-3 replicas, GDPR/audit enabled
- Add environment-specific configMapGenerator with LOG_LEVEL, ENVIRONMENT, RATE_LIMIT settings
- Add environment-specific secretGenerator with DATABASE_URL, REDIS_URL, JWT_SECRET, encryption key (prod

deployments/environments/dev/kustomization.yaml

@@ -0,0 +1,40 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+metadata:
+  name: telecom-platform-dev
+resources:
+- ../../kubernetes/00-namespace.yaml
+- ../../kubernetes/01-mongodb.yaml
+- ../../kubernetes/02-redis.yaml
+- ../../kubernetes/03-api-server.yaml
+- ../../kubernetes/04-charging-engine.yaml
+- ../../kubernetes/manifests/
+patchesStrategicMerge:
+- api-server-dev-patch.yaml
+- charging-engine-dev-patch.yaml
+namespace: telecom-platform-dev
+commonLabels:
+  app.kubernetes.io/environment: dev
+  app.kubernetes.io/managed-by: kustomize
+configMapGenerator:
+- name: telecom-platform-config
+  literals:
+  - LOG_LEVEL=debug
+  - ENVIRONMENT=dev
+  - RATE_LIMIT_REQUESTS=100
+  - RATE_LIMIT_WINDOW=60
+secretGenerator:
+- name: telecom-platform-secrets
+  literals:
+  - DATABASE_URL=postgresql://postgres:dev123@postgres:5432/telecom_dev
+  - REDIS_URL=redis://redis:6379
+  - JWT_SECRET=dev-jwt-secret-key
+replicas:
+- name: api-server
+  count: 1
+- name: charging-engine
+  count: 1
+- name: packet-gateway
+  count: 1
+- name: web-dashboard
+  count: 1