refactor: unify kubernetes_ table prefix, merge CI/CD models, LLM session support

- Rename container_clusters → kubernetes_clusters, container_topology_layouts → kubernetes_topology_layouts
- LLM: add session_id to chat history for multi-turn conversation support
- CI/CD: add pipeline_id, deploy_type, artifact_url, k8s_cluster_id to AppRelease
- Cleanup: remove deprecated playbook handler, simplify automation models
- Database: optimize auto-migrate model list
- Frontend: AIOps assistant improvements, api.ts updates

backend/internal/models/kubernetes.go

@@ -32,7 +32,7 @@ type KubernetesCluster struct {
 
 // TableName 表名
 func (KubernetesCluster) TableName() string {
-	return "container_clusters"
+	return "kubernetes_clusters"
 }
 
 // KubernetesNode K8s节点模型
@@ -198,5 +198,5 @@ type TopologyLayout struct {
 
 // TableName 指定表名
 func (TopologyLayout) TableName() string {
-	return "container_topology_layouts"
+	return "kubernetes_topology_layouts"
 }