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/pkg/utils/message.go

@@ -1,11 +1,11 @@
 package utils
 
 import (
+	"bytes"
 	"code.tczkiot.com/wlw/ai-agent/internal/models"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/enums"
 	"code.tczkiot.com/wlw/ai-agent/internal/repositories"
 	"code.tczkiot.com/wlw/ai-agent/internal/services/storage"
-	"bytes"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -16,13 +16,28 @@ import (
 )
 
 type imMessageAssetPayload struct {
-	AssetID    string              `json:"assetId"`
-	Provider   enums.AssetProvider `json:"provider,omitempty"`
-	StorageKey string              `json:"storageKey,omitempty"`
-	Filename   string              `json:"filename,omitempty"`
-	FileSize   int64               `json:"fileSize,omitempty"`
-	MimeType   string              `json:"mimeType,omitempty"`
-	URL        string              `json:"url,omitempty"`
+	AssetID    string                  `json:"asset_id,omitempty"`
+	Provider   enums.AssetProvider     `json:"provider,omitempty"`
+	StorageKey string                  `json:"storage_key,omitempty"`
+	Filename   string                  `json:"filename,omitempty"`
+	FileSize   int64                   `json:"file_size,omitempty"`
+	MimeType   string                  `json:"mime_type,omitempty"`
+	URL        string                  `json:"url,omitempty"`
+	Assets     []imMessageAssetPayload `json:"assets,omitempty"`
+}
+
+func (p *imMessageAssetPayload) items() []*imMessageAssetPayload {
+	if p == nil {
+		return nil
+	}
+	if len(p.Assets) == 0 {
+		return []*imMessageAssetPayload{p}
+	}
+	items := make([]*imMessageAssetPayload, 0, len(p.Assets))
+	for index := range p.Assets {
+		items = append(items, &p.Assets[index])
+	}
+	return items
 }
 
 func SanitizeMessageHTML(content string) string {
@@ -111,8 +126,8 @@ func BuildRuntimeMessageText(messageType enums.IMMessageType, content string) st
 	case enums.IMMessageTypeHTML:
 		return BuildHTMLSummary(content)
 	case enums.IMMessageTypeImage:
-		if content != "" {
-			return "[图片] " + content
+		if text := BuildHTMLSummary(content); text != "" {
+			return "[图片] " + text
 		}
 		return "[图片]"
 	case enums.IMMessageTypeAttachment:
@@ -286,10 +301,12 @@ func buildIMMessageAssetPayloadForResponse(payload string) string {
 	if err != nil {
 		return strings.TrimSpace(payload)
 	}
-	assetPayload = hydrateIMMessageAssetPayload(assetPayload)
-	if assetPayload.Provider != "" && assetPayload.StorageKey != "" {
-		if provider, err := storage.NewProvider(assetPayload.Provider); err == nil {
-			assetPayload.URL = provider.GetSignedURL(assetPayload.StorageKey)
+	for _, item := range assetPayload.items() {
+		hydrateIMMessageAssetPayload(item)
+		if item.Provider != "" && item.StorageKey != "" {
+			if provider, err := storage.NewProvider(item.Provider); err == nil {
+				item.URL = provider.GetSignedURL(item.StorageKey)
+			}
 		}
 	}
 	data, err := json.Marshal(assetPayload)
@@ -308,9 +325,11 @@ func parseIMMessageAssetPayload(payload string) (*imMessageAssetPayload, error)
 	if err := json.Unmarshal([]byte(payload), ret); err != nil {
 		return nil, err
 	}
-	ret.AssetID = strings.TrimSpace(ret.AssetID)
-	ret.Provider = enums.AssetProvider(strings.TrimSpace(string(ret.Provider)))
-	ret.StorageKey = strings.TrimSpace(ret.StorageKey)
+	for _, item := range ret.items() {
+		item.AssetID = strings.TrimSpace(item.AssetID)
+		item.Provider = enums.AssetProvider(strings.TrimSpace(string(item.Provider)))
+		item.StorageKey = strings.TrimSpace(item.StorageKey)
+	}
 	return ret, nil
 }