feat(ai-service): 替换 anonymous 为随机访客唯一标识 getUserId()

- 新增 getUserId() 函数，已登录返回 memberId，未登录生成并持久化 guest_* 唯一ID
- 替换全部 10 处 'anonymous' 硬编码为 getUserId()

common/js/ai-service.js

@@ -26,6 +26,29 @@ try {
   console.warn('读取会话ID失败:', e);
 }
 
+const GUEST_ID_KEY = 'ai_guest_user_id';
+
+/**
+ * 获取用户ID：已登录返回 memberId，未登录生成访客唯一标识并持久化
+ */
+function getUserId() {
+  const memberId = store.state.memberInfo?.id;
+  if (memberId) return memberId;
+  
+  let guestId;
+  try {
+    guestId = uni.getStorageSync(GUEST_ID_KEY);
+  } catch (e) { /* ignore */ }
+  
+  if (!guestId) {
+    guestId = 'guest_' + Date.now() + '_' + Math.random().toString(36).slice(2, 10);
+    try {
+      uni.setStorageSync(GUEST_ID_KEY, guestId);
+    } catch (e) { /* ignore */ }
+  }
+  return guestId;
+}
+
 // #ifdef MP-WEIXIN
 // ================================
 // WebSocket 长连接管理（微信小程序）
@@ -75,7 +98,7 @@ function ensureWebSocketConnected() {
     // 获取认证参数（独立函数，不使用 this）
     var _uniacid = uni.getStorageSync('uniacid') || Config.uniacid;
     var _token = store.state.token || 'test_token';
-    var _userId = store.state.memberInfo?.id || 'anonymous';
+    var _userId = getUserId();
 
     wsSocketTask.onOpen(function() {
       wsConnected = true;
@@ -217,12 +240,12 @@ export default {
       const params = {
         url: '/api/kefu/chat',
         data: {
-          user_id: store.state.memberInfo?.id || 'anonymous',
+          user_id: getUserId(),
           stream: false,
           inputs: {},
           query: message,
           response_mode: 'blocking', // 强制 blocking
-          user: store.state.memberInfo?.id || 'anonymous',
+          user: getUserId(),
           conversation_id: this.getConversationId() || '',
           ...getDomainParams()
         },
@@ -283,7 +306,7 @@ export default {
           action: 'chat',
           uniacid: this.getUniacid(),
           query: message,
-          user_id: store.state.memberInfo?.id || 'anonymous',
+          user_id: getUserId(),
           conversation_id: this.getConversationId() || '',
           ...getDomainParams()
         })
@@ -310,7 +333,7 @@ export default {
           inputs: {},
           query: message,
           response_mode: 'streaming',
-          user_id: store.state.memberInfo?.id || 'anonymous',
+          user_id: getUserId(),
           conversation_id: this.getConversationId() || '',
           ...getDomainParams()
         })
@@ -462,8 +485,8 @@ export default {
       data: {
         uniacid: this.getUniacid(),
         token: store.state.token || 'test_token',
-        user_id: store.state.memberInfo?.id || 'anonymous',
-        member_id: store.state.memberInfo?.id || 'anonymous',
+        user_id: getUserId(),
+        member_id: getUserId(),
         ...getDomainParams()
       },
       header: {
@@ -533,10 +556,10 @@ export default {
       const requestData = {
         uniacid: params.uniacid || this.getUniacid(),
         conversation_id: params.conversation_id,
-        user_id: params.user_id || store.state.memberInfo?.id || 'anonymous',
+        user_id: params.user_id || getUserId(),
         limit: params.limit || 20,
         offset: params.offset || 0,
-        member_id: params.member_id || store.state.memberInfo?.id || 'anonymous',
+        member_id: params.member_id || getUserId(),
         token: params.token || '',
         ...getDomainParams()
       };
@@ -579,8 +602,8 @@ export default {
     }
     const paramsObj = {
       uniacid: this.getUniacid(),
-      user_id: store.state.memberInfo?.id || 'anonymous',
-      member_id: store.state.memberInfo?.id || 'anonymous',
+      user_id: getUserId(),
+      member_id: getUserId(),
       token: store.state.token || 'test_token',
       query: message,
       conversation_id: conversationId || '',