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/services/knowledge_base_service.go

@@ -2,14 +2,9 @@ package services
 
 import (
 	"context"
-	"encoding/json"
-	"fmt"
-	"strings"
 	"time"
 
 	"code.tczkiot.com/wlw/ai-agent/internal/ai/rag"
-	"code.tczkiot.com/wlw/ai-agent/internal/ai/workflow/dsl"
-	workflowregistry "code.tczkiot.com/wlw/ai-agent/internal/ai/workflow/registry"
 	"code.tczkiot.com/wlw/ai-agent/internal/models"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/dto"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/dto/request"
@@ -133,14 +128,6 @@ func (s *knowledgeBaseService) DeleteKnowledgeBase(id int64) error {
 		return errorsx.InvalidParamI18n("error.e0283")
 	}
 
-	referencingWorkflows := s.findWorkflowReferencesByKnowledgeBaseID(id)
-	if len(referencingWorkflows) > 0 {
-		if len(referencingWorkflows) == 1 {
-			return errorsx.Forbidden(fmt.Sprintf("知识库正在被流程「%s」使用，请先从知识检索节点中移除", referencingWorkflows[0]))
-		}
-		return errorsx.Forbidden(fmt.Sprintf("知识库正在被 %d 个流程使用，请先从知识检索节点中移除", len(referencingWorkflows)))
-	}
-
 	if err := sqls.WithTransaction(func(ctx *sqls.TxContext) error {
 		if err := repositories.KnowledgeDocumentRepository.DeleteByKnowledgeBaseID(ctx.Tx, id); err != nil {
 			return err
@@ -156,86 +143,6 @@ func (s *knowledgeBaseService) DeleteKnowledgeBase(id int64) error {
 	return rag.Index.RemoveKnowledgeBaseIndex(context.Background(), id)
 }
 
-func (s *knowledgeBaseService) findWorkflowReferencesByKnowledgeBaseID(id int64) []string {
-	names := make(map[string]struct{})
-	workflows := repositories.AIWorkflowRepository.Find(sqls.DB(), sqls.NewCnd().Eq("status", enums.StatusOk))
-	workflowNames := make(map[int64]string, len(workflows))
-	for _, workflow := range workflows {
-		name := strings.TrimSpace(workflow.Name)
-		if name == "" {
-			name = fmt.Sprintf("ID %d", workflow.ID)
-		}
-		workflowNames[workflow.ID] = name
-		if workflowDefinitionUsesKnowledgeBase(workflow.DraftDefinition, id) {
-			names[name] = struct{}{}
-		}
-	}
-	versions := repositories.AIWorkflowVersionRepository.Find(sqls.DB(), sqls.NewCnd())
-	for _, version := range versions {
-		if !workflowDefinitionUsesKnowledgeBase(version.Definition, id) {
-			continue
-		}
-		name := workflowNames[version.WorkflowID]
-		if strings.TrimSpace(name) == "" {
-			name = fmt.Sprintf("ID %d", version.WorkflowID)
-		}
-		names[name] = struct{}{}
-	}
-	ret := make([]string, 0, len(names))
-	for name := range names {
-		ret = append(ret, name)
-	}
-	return ret
-}
-
-func workflowDefinitionUsesKnowledgeBase(definition string, id int64) bool {
-	definition = strings.TrimSpace(definition)
-	if definition == "" {
-		return false
-	}
-	var def dsl.Definition
-	if err := json.Unmarshal([]byte(definition), &def); err != nil {
-		return false
-	}
-	for _, node := range def.Nodes {
-		if strings.TrimSpace(node.Type) != workflowregistry.NodeTypeKnowledgeRetrieve {
-			continue
-		}
-		for _, knowledgeBaseID := range knowledgeBaseIDsFromWorkflowNodeConfig(node.Data.Config) {
-			if knowledgeBaseID == id {
-				return true
-			}
-		}
-	}
-	return false
-}
-
-func knowledgeBaseIDsFromWorkflowNodeConfig(raw json.RawMessage) []int64 {
-	if len(raw) == 0 {
-		return nil
-	}
-	var cfg map[string]any
-	if err := json.Unmarshal(raw, &cfg); err != nil {
-		return nil
-	}
-	items, ok := cfg["knowledgeBaseIds"].([]any)
-	if !ok {
-		return nil
-	}
-	ret := make([]int64, 0, len(items))
-	for _, item := range items {
-		switch value := item.(type) {
-		case float64:
-			ret = append(ret, int64(value))
-		case int64:
-			ret = append(ret, value)
-		case int:
-			ret = append(ret, int64(value))
-		}
-	}
-	return ret
-}
-
 func (s *knowledgeBaseService) UpdateSort(ids []int64) error {
 	return sqls.WithTransaction(func(ctx *sqls.TxContext) error {
 		for i, id := range ids {