feat: 健康体检胃肠镜预选与预约流程完善（新增胃肠镜医院预选征集页与已提交页、检前首页预选通知条，唐都医院问卷新增就诊卡必填题与办理流程弹窗，选日期页新增预约状态条与可约窗口限制（常规近30天/胃肠镜7~30天）与提交loading过渡，预约结果页新增成功/失败演示切换与取消预约二次确认弹窗，预约类型/我的预约页精简，胃肠镜报告页影像报告整合并新增下载入口，首页站点地图同步）

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

index.html

@@ -593,6 +593,8 @@ const SITE_MAP = [
       { file:'booking-project-selected.html', label:'预约-已选项目' },
       { file:'booking-date.html', label:'预约-选择日期' },
       { file:'booking-date-selected.html', label:'预约-已选日期' },
+      { 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:'我的预约' },
       { file:'hospital-checkin.html', label:'到院体检' },
       { file:'reports.html', label:'体检报告' },