feat(pdd-ui): 新增管理后台拼多多店铺CRUD与Cookie有效性实时检测功能

1. 订单快照优化 (pdd-order-mapper.ts):
   - 在 item_snapshot_json 中完整保留拼多多原始报文快照全量字段，确保无信息截断。

2. 后端 Cookie 有效性校验接口 (pdd-client.ts, platform-config/pdd.ts):
   - 新增 PddClient.testCookie 与 POST /api/v1/admin/platform-config/pdd/test-cookie 接口。
   - 支持通过轻量接口请求即时测试 Cookie 合法性，精准识别有效状态（返回在线订单数）与失效/频控状态。

3. 前端管理面板开发 (PddPlatformPanel.tsx, AdminPlatformShopsPage.tsx):
   - 在平台配置页面新增【拼多多 (PDD)】专属 Tab 面板。
   - 提供拼多多全局同步开关与轮询间隔配置。
   - 支持店铺完整 CRUD：添加店铺、编辑店铺、删除店铺、启用/停用切换。
   - 支持弹窗内即时【测试此 Cookie 有效性】（无需先保存即可验证）及列表行内一键测活与单店铺立即同步。

apps/backend/src/services/platforms/pdd/pdd-client.ts

@@ -11,6 +11,8 @@
  *   自动生成合规 0as Anti-Content 并双向注入网关请求头与报文体。
  * - Structured MMS error resolution (Rate limit 40002, Auth expired 40001).
  *   结构化捕获与解析拼多多业务级错误（频控 40002、Cookie 失效 40001 等）。
+ * - Live Cookie validity verification with latency metrics.
+ *   商家 Cookie 有效性在线实测校验与连通性检测。
  */
 
 import { pddAntiContentEngine, PurePddAntiContent } from './pdd-anti-content.js'
@@ -42,6 +44,13 @@ export interface PddOrderQueryResult {
   items: PddRawOrderItem[]
 }
 
+export interface PddTestCookieResult {
+  valid: boolean
+  message: string
+  totalOrders?: number | undefined
+  firstOrderSn?: string | undefined
+}
+
 export class PddClient {
   public static readonly BASE_URL = 'https://mms.pinduoduo.com'
   public static readonly RECENT_ORDERS_API = `${PddClient.BASE_URL}/mangkhut/mms/recentOrderList`
@@ -219,4 +228,78 @@ export class PddClient {
       items,
     }
   }
+
+  /**
+   * Test Cookie validity by sending a single lightweight query to MMS API.
+   * 通过发送轻量请求验证拼多多商家 Cookie 的有效性与网关连通性。
+   */
+  public static async testCookie(credentials: {
+    cookie: string
+    userAgent?: string | undefined
+  }): Promise<PddTestCookieResult> {
+    const cookie = (credentials.cookie || '').trim()
+    if (!cookie) {
+      return {
+        valid: false,
+        message: 'Cookie 不能为空 / Cookie string cannot be empty',
+      }
+    }
+
+    const client = new PddClient({
+      shopId: 'cookie_test',
+      shopName: 'Cookie 测试',
+      cookie,
+      userAgent: credentials.userAgent,
+    })
+
+    try {
+      const result = await client.queryRecentOrders({
+        pageNumber: 1,
+        pageSize: 1,
+        orderType: 0,
+      })
+
+      const firstItem = result.items[0]
+      return {
+        valid: true,
+        message: `Cookie 有效，网关校验通过（店铺在售/历史订单数: ${result.total}）`,
+        totalOrders: result.total,
+        firstOrderSn: firstItem?.order_sn,
+      }
+    } catch (err) {
+      const errMsg = err instanceof Error ? err.message : String(err)
+      if (
+        errMsg.includes('40001') ||
+        errMsg.includes('登录') ||
+        errMsg.includes('失效') ||
+        errMsg.includes('未登录')
+      ) {
+        return {
+          valid: false,
+          message: `Cookie 已失效或登录已过期: ${errMsg}`,
+        }
+      }
+      if (errMsg.includes('40002') || errMsg.includes('频控')) {
+        return {
+          valid: false,
+          message: `触发网关频控 (40002): 操作过于频繁，请稍后重试`,
+        }
+      }
+      return {
+        valid: false,
+        message: `验证未通过: ${errMsg}`,
+      }
+    }
+  }
+}
+
+/**
+ * Convenient helper to test Cookie validity.
+ * 便捷辅助函数：测试 Cookie 有效性。
+ */
+export function testPddCookie(credentials: {
+  cookie: string
+  userAgent?: string | undefined
+}): Promise<PddTestCookieResult> {
+  return PddClient.testCookie(credentials)
 }

apps/backend/src/services/platforms/pdd/pdd-order-mapper.ts

@@ -80,7 +80,9 @@ export function mapPddOrderToSourceEvent(
   const skuName = spec ? `${goodsName} (${spec})` : goodsName
   const externalSkuCode = goodsIdStr
 
+  // Retain the entire raw snapshot dictionary as requested / 保留原始报文完整快照
   const itemSnapshot: JsonObject = {
+    ...(rawOrder as unknown as JsonObject),
     goodsId: goodsIdStr,
     goodsName,
     spec,
@@ -92,7 +94,6 @@ export function mapPddOrderToSourceEvent(
     nickname: String(rawOrder.nickname || ''),
     orderTime: rawOrder.order_time,
     confirmTime: rawOrder.confirm_time,
-    pddRaw: rawOrder as unknown as JsonObject,
   }
 
   return {