支持客服入口按业务场景分流到客服分组

联系客服支持 scene（general/mohong），按用户与场景复用会话；摸大红入口走摸大红分组选人。

frontend/src/features/listings/views/MobileHomeView.vue

@@ -3,7 +3,7 @@ import { computed, nextTick, onBeforeUnmount, onMounted, ref, watch } from 'vue'
 import { onBeforeRouteLeave, RouterLink, useRoute, useRouter } from 'vue-router'
 import { showToast } from 'vant'
 import MobileBottomNav from '@/components/MobileBottomNav.vue'
-import { ensureSupportChat } from '@/features/chats/api/chats'
+import { ensureSupportChat, resolveSupportScene } from '@/features/chats/api/chats'
 import { formatCent, formatMoney } from '@/shared/utils/money'
 import {
   emptyListingPublishOptions,
@@ -158,7 +158,8 @@ async function handleSupportClick() {
   if (supportLoading.value) return
   supportLoading.value = true
   try {
-    const chat = await ensureSupportChat()
+    const scene = resolveSupportScene(route.path)
+    const chat = await ensureSupportChat(scene)
     router.push(`/m/chats/${chat.id}`)
   } catch {
     showToast({ message: '联系客服失败，请稍后重试', icon: 'cross' })