feat: 企微绑定入口 — BindWechat.vue + 路由

新增 /bind-wechat 公开路由:
- 页面加载后自动重定向到企微 OAuth 授权页
- scope=snsapi_base (静默授权，无需用户确认)
- 回调到 /login?wecom_code=xxx → 自动绑定

用法: 企微工作台应用主页设为 https://qj.dhdx.fun/bind-wechat

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

frontend/src/router/index.ts

@@ -16,6 +16,12 @@ const router = createRouter({
       component: () => import('@/views/BindWecom.vue'),
       meta: { public: true },
     },
+    {
+      path: '/bind-wechat',
+      name: 'BindWechat',
+      component: () => import('@/views/BindWechat.vue'),
+      meta: { public: true },
+    },
     // Mobile routes (manager-facing)
     {
       path: '/m',

frontend/src/views/BindWechat.vue

@@ -0,0 +1,30 @@
+<script setup lang="ts">
+import { onMounted } from 'vue'
+
+const CORP_ID = 'ww69e8e44636f47780'
+const REDIRECT_URI = encodeURIComponent('https://qj.dhdx.fun/login')
+const STATE = 'bind'
+
+onMounted(() => {
+  const url = `https://open.weixin.qq.com/connect/oauth2/authorize?appid=${CORP_ID}&redirect_uri=${REDIRECT_URI}&response_type=code&scope=snsapi_base&state=${STATE}#wechat_redirect`
+  window.location.href = url
+})
+</script>
+
+<template>
+  <div class="bind-wechat-page">
+    <p>正在跳转企业微信授权...</p>
+  </div>
+</template>
+
+<style scoped>
+.bind-wechat-page {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  height: 100vh;
+  font-size: 16px;
+  color: var(--ink);
+  font-family: 'Noto Serif SC', STSong, serif;
+}
+</style>