feat: 四端设计总览生成、截图补全与模板工具链完善

- 新增 operator/onsite/professional/employee-app 四端 design-overview.html
- 补全约 30 张弹窗/状态截图，重拍长图（fullPage）
- 新增 design-overview-template.html 模板与 design-overview skill
- index.html 注册设计总览入口、修复 md-viewer 路径
- 删除已迁移的 md-viewer.html 和本地服务器方案文档
- 更新 package.json 依赖与项目背景文档

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

index.html

@@ -559,6 +559,7 @@ const SITE_MAP = [
       { file:'consult-flowchart.html', label:'咨询流程图' }
     ]},
     { name:'应急就医', dir:'employee-app/emergency-medical', entry:'index.html', prd:'employee-app/emergency-medical/doc/PRD.md', done:true, pages:[
+      { file:'doc/design-overview.html', label:'页面总览' },
       { file:'index.html', label:'应急就医主页' },
       { file:'emergency-chat.html', label:'应急对话' },
       { file:'resource-map.html', label:'应急资源地图' },
@@ -645,6 +646,7 @@ const SITE_MAP = [
       ]},
       { role:'应急操作人员', id:'operator', modules:[
         {name:'工作台',dir:'emergency-app/operator/workbench',prd:'emergency-app/operator/doc/PRD.md',done:true,pages:[
+          {file:'../doc/design-overview.html',label:'页面总览'},
           {file:'index.html',label:'工作台首页(应急求助)'},
           {file:'serious-illness-list.html',label:'大病就医首页'},
           {file:'emergency-chat.html',label:'应急聊天'},
@@ -673,6 +675,7 @@ const SITE_MAP = [
       ]},
       { role:'应急专业人员', id:'professional', modules:[
         { name:'工作台', dir:'emergency-app/professional/workbench', prd:'emergency-app/professional/doc/PRD.md', done:true, pages:[
+          {file:'../doc/design-overview.html',label:'页面总览'},
           {file:'index.html',label:'工作台首页'},
           {file:'emergency-chat-ongoing.html',label:'应急聊天(进行中)'},
           {file:'emergency-chat-done.html',label:'应急聊天(已结束)'},
@@ -692,6 +695,7 @@ const SITE_MAP = [
       ]},
       { role:'应急驻场人员', id:'onsite', modules:[
         {name:'工作台',dir:'emergency-app/onsite/workbench',prd:'emergency-app/onsite/doc/PRD.md',done:true,pages:[
+          {file:'../doc/design-overview.html',label:'页面总览'},
           {file:'index.html',label:'工作台首页(应急求助)'},
           {file:'serious-illness-list.html',label:'大病就医首页'},
           {file:'work-order-detail-ongoing.html',label:'工单详情(待处理)'},
@@ -968,7 +972,7 @@ tabNav.addEventListener('click', e => {
 
 /* ===== Markdown 预览（新标签页打开） ===== */
 function openMdPreview(filePath, title) {
-  window.open('md-viewer.html?file=' + encodeURIComponent(filePath) + '&title=' + encodeURIComponent(title || ''), '_blank');
+  window.open('_templates/md-viewer.html?file=' + encodeURIComponent(filePath) + '&title=' + encodeURIComponent(title || ''), '_blank');
 }
 </script>
 </body>