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/subject_service.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"strings"
 	"sync"
 
 	"code.tczkiot.com/wlw/ai-agent/identity"
@@ -75,12 +76,37 @@ func (s *subjectService) CurrentExternal(ctx context.Context) (*openidentity.Ext
 		ExternalSource: enums.ExternalSourceUser,
 		ExternalID:     fmt.Sprintf("%s:%d", subject.Type, subject.ID),
 		ExternalName:   subject.Name,
+		SubjectType:    subject.Type,
+		SubjectID:      subject.ID,
+	}, nil
+}
+
+// ResolveExternal returns a host-authenticated customer when available and
+// falls back to the opaque browser identifier used by anonymous Web visitors.
+// The identifier is not a login token and is never accepted for dashboard APIs.
+func (s *subjectService) ResolveExternal(ctx context.Context, guestID, guestName string) (*openidentity.ExternalUser, error) {
+	external, err := s.CurrentExternal(ctx)
+	if err == nil {
+		return external, nil
+	}
+	guestID = strings.TrimSpace(guestID)
+	if guestID == "" || len(guestID) > 128 {
+		return nil, err
+	}
+	guestName = strings.TrimSpace(guestName)
+	if len(guestName) > 255 {
+		guestName = guestName[:255]
+	}
+	return &openidentity.ExternalUser{
+		ExternalSource: enums.ExternalSourceGuest,
+		ExternalID:     guestID,
+		ExternalName:   guestName,
 	}, nil
 }
 
 func (s *subjectService) Get(id int64) *identity.Subject {
 	items, err := s.Query(context.Background(), identity.Query{
-		Types:       []identity.SubjectType{identity.SubjectAgent},
+		Types:       []identity.SubjectType{identity.SubjectAdmin},
 		IDs:         []int64{id},
 		EnabledOnly: true,
 	})
@@ -99,7 +125,7 @@ func (s *subjectService) FindByIDs(ids []int64) []identity.Subject {
 		return nil
 	}
 	items, err := s.Query(context.Background(), identity.Query{
-		Types:       []identity.SubjectType{identity.SubjectAgent},
+		Types:       []identity.SubjectType{identity.SubjectAdmin},
 		IDs:         ids,
 		EnabledOnly: true,
 	})
@@ -109,3 +135,24 @@ func (s *subjectService) FindByIDs(ids []int64) []identity.Subject {
 	}
 	return items
 }
+
+func (s *subjectService) IsUserReference(subjectType identity.SubjectType, id int64) bool {
+	if id <= 0 {
+		return false
+	}
+	switch subjectType {
+	case identity.SubjectCard, identity.SubjectDevice, identity.SubjectMallUser:
+	default:
+		return false
+	}
+	items, err := s.Query(context.Background(), identity.Query{
+		Types:       []identity.SubjectType{subjectType},
+		IDs:         []int64{id},
+		EnabledOnly: true,
+	})
+	if err != nil {
+		slog.Warn("query external customer subject failed", "type", subjectType, "id", id, "error", err)
+		return false
+	}
+	return len(items) > 0
+}