Add WeChat miniprogram web-view shell

miniprogram/pages/web-view/index.wxml

@@ -0,0 +1,15 @@
+<block wx:if="{{webViewUrl}}">
+  <web-view
+    src="{{webViewUrl}}"
+    bindload="handleWebViewLoad"
+    binderror="handleWebViewError"
+    bindmessage="handleWebViewMessage"
+  />
+</block>
+
+<view wx:else class="setup-screen">
+  <view class="setup-card">
+    <view class="setup-title">需要配置 H5 入口</view>
+    <view class="setup-text">请先在 miniprogram/config.js 填写 WEB_VIEW_ENTRY_URL。</view>
+  </view>
+</view>