用户消息系统：消息列表、订单群聊、联系对方入口

- 新增消息列表页和聊天详情页，支持 SSE 实时推送
- 订单详情页新增"联系对方"按钮，一键进入订单群聊
- 导航栏新增"消息"入口
- 修复 mobileHost 路径匹配 bug，避免 /m 前缀误匹配
- 优化 dev.sh：提取 mysql 辅助函数、修复空 PID 处理、条件检查依赖

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/views/account/OrderDetailView.vue

@@ -1,8 +1,10 @@
 <script setup lang="ts">
 import { ElMessage } from 'element-plus'
+import { ChatDotRound } from '@element-plus/icons-vue'
 import { computed, onMounted, ref } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 
+import { fetchOrderChat } from '@/api/chats'
 import { createDispute } from '@/api/disputes'
 import { uploadFile } from '@/api/files'
 import {
@@ -61,6 +63,7 @@ const rejectReason = ref('')
 const disputeType = ref('cannot_login')
 const disputeDescription = ref('')
 const disputeEvidenceText = ref('')
+const openingChat = ref(false)
 
 const isOwner = computed(() => order.value?.owner_id === session.userId)
 const isRenter = computed(() => order.value?.renter_id === session.userId)
@@ -300,6 +303,19 @@ async function handleEvidenceUpload(event: Event) {
   }
 }
 
+async function openOrderChat() {
+  if (!order.value || openingChat.value) return
+  openingChat.value = true
+  try {
+    const chat = await fetchOrderChat(order.value.id)
+    await router.push(`/messages/${chat.id}`)
+  } catch {
+    ElMessage.error('订单群聊暂不可用')
+  } finally {
+    openingChat.value = false
+  }
+}
+
 function readError(error: unknown, fallback: string) {
   if (typeof error === 'object' && error && 'response' in error) {
     const response = (error as { response?: { data?: { message?: string } } }).response
@@ -463,7 +479,13 @@ function linesToList(value: string) {
     <div v-if="order" class="page-header">
       <p class="eyebrow">{{ order.order_no }}</p>
       <h1>订单详情</h1>
-      <p>{{ order.title }} · {{ order.server_region }} / {{ order.login_platform }}</p>
+      <div class="header-actions">
+        <p>{{ order.title }} · {{ order.server_region }} / {{ order.login_platform }}</p>
+        <el-button type="primary" :loading="openingChat" @click="openOrderChat">
+          <el-icon style="margin-right: 4px;"><ChatDotRound /></el-icon>
+          联系对方
+        </el-button>
+      </div>
     </div>
 
     <div v-if="order" class="detail-grid">
@@ -644,6 +666,17 @@ function linesToList(value: string) {
 </template>
 
 <style scoped>
+.header-actions {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.header-actions p {
+  margin: 0;
+}
+
 .checkout-resource-panel {
   display: grid;
   gap: 10px;