feat: 健康体检精简页面并统一术语为已参检

- 删除到院体检(hospital-checkin)与未开展计划(index-inactive)页面及对应截图
- 术语统一:已体检→已参检,操作流程讲解→操作说明
- 选择体检类型页优化:移除体检状态徽标,字段改为计划起止日期/预约开放日期/当前所属群体
- 补充预约项目AI解读、提交及胃肠镜预选/问卷相关截图
- 同步更新PRD文档与全站导航配置

index.html

@@ -661,7 +661,6 @@ const SITE_MAP = [
     ] },
     { name:'健康体检', dir:'employee-app/health-checkup', entry:'index.html', prd:'employee-app/health-checkup/doc/PRD.md', pages:[
       { file:'index.html', label:'健康体检主页' },
-      { file:'index-inactive.html', label:'健康体检-未开展' },
       { file:'booking-type.html', label:'选择体检类型' },
       { file:'booking-hospital.html', label:'预约-选择医院' },
       { file:'booking-project.html', label:'预约-选择项目' },
@@ -671,7 +670,6 @@ const SITE_MAP = [
       { file:'gastro-preselect.html', label:'胃肠镜医院预选' },
       { file:'gastro-preselect-done.html', label:'胃肠镜预选-已提交' },
       { file:'my-appointments-all.html', label:'现场体检' },
-      { file:'hospital-checkin.html', label:'到院体检' },
       { file:'reports.html', label:'体检报告' },
       { file:'report-query.html', label:'报告查询详情' },
       { file:'indicator-compare.html', label:'指标纵向对比总览' },