refactor: 将客服后端重构为宿主可嵌入模块

- 注入数据库、运行时配置、统一响应、文件存储和平台 AI 能力，补充业务读写工具与客户快捷操作契约。

- 移除模块内重复的组织、客户、工单、标签、技能、旧工作流、MCP 和迁移实现，将身份权限与业务主体交由宿主管理。

- 使用 libSQL 重构向量存储，并完善图片消息、访客身份、排队调度、企业微信和支持聊天页面。

- 统一 HTTP、DTO 与 WebSocket 的 snake_case 协议，补齐模块初始化、业务动作和公共载荷等回归测试。

internal/ai/runtime/registry/registry_test.go

@@ -21,8 +21,8 @@ func (t stubTool) Spec() toolx.ToolSpec {
 	return toolx.ToolSpec{
 		Code:       t.code,
 		Name:       t.name,
-		ServerCode: toolx.GraphCreateTicketConfirm.ServerCode,
-		SourceType: toolx.GraphCreateTicketConfirm.SourceType,
+		ServerCode: toolx.GraphHandoffConversation.ServerCode,
+		SourceType: toolx.GraphHandoffConversation.SourceType,
 	}
 }
 
@@ -45,8 +45,8 @@ func (t stubBaseTool) Info(context.Context) (*schema.ToolInfo, error) {
 
 func TestResolveBuildsStaticToolMetadata(t *testing.T) {
 	r := registry.NewRegistry(stubTool{
-		name: toolx.GraphCreateTicketConfirm.Name,
-		code: toolx.GraphCreateTicketConfirm.Code,
+		name: toolx.GraphHandoffConversation.Name,
+		code: toolx.GraphHandoffConversation.Code,
 	})
 	toolSet, err := r.Resolve(registry.Context{
 		Conversation: models.Conversation{ID: 1},
@@ -61,20 +61,20 @@ func TestResolveBuildsStaticToolMetadata(t *testing.T) {
 	if len(toolSet.StaticToolMetadata) != 1 {
 		t.Fatalf("expected 1 metadata item, got %d", len(toolSet.StaticToolMetadata))
 	}
-	item, ok := toolSet.StaticToolMetadata[toolx.GraphCreateTicketConfirm.Name]
+	item, ok := toolSet.StaticToolMetadata[toolx.GraphHandoffConversation.Name]
 	if !ok {
-		t.Fatalf("missing metadata for %s", toolx.GraphCreateTicketConfirm.Name)
+		t.Fatalf("missing metadata for %s", toolx.GraphHandoffConversation.Name)
 	}
-	if item.ToolCode != toolx.GraphCreateTicketConfirm.Code {
+	if item.ToolCode != toolx.GraphHandoffConversation.Code {
 		t.Fatalf("unexpected tool code: %s", item.ToolCode)
 	}
-	if item.ServerCode != toolx.GraphCreateTicketConfirm.ServerCode {
+	if item.ServerCode != toolx.GraphHandoffConversation.ServerCode {
 		t.Fatalf("unexpected server code: %s", item.ServerCode)
 	}
-	if item.ToolName != toolx.GraphCreateTicketConfirm.Name {
+	if item.ToolName != toolx.GraphHandoffConversation.Name {
 		t.Fatalf("unexpected tool name: %s", item.ToolName)
 	}
-	if item.SourceType != toolx.GraphCreateTicketConfirm.SourceType {
+	if item.SourceType != toolx.GraphHandoffConversation.SourceType {
 		t.Fatalf("unexpected source type: %s", item.SourceType)
 	}
 }