feat(templates): confirm before leaving wizard with draft content

Intercept route changes and tab close when the template wizard has
unsubmitted content so users can save a draft, discard, or stay instead
of silently losing their progress.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/i18n/messages/en-US.ts

@@ -939,6 +939,13 @@ const enUS = {
         queued: 'Task submitted. The article is now waiting in the generation queue.',
         submitted: 'Generation task submitted. Refreshing article data.',
       },
+      leaveConfirm: {
+        title: 'Save as draft?',
+        content: 'This template wizard has content. Save it as a draft before leaving.',
+        stay: 'Keep editing',
+        discard: 'Leave without saving',
+        save: 'Save draft',
+      },
     },
   },
   article: {

apps/admin-web/src/i18n/messages/zh-CN.ts

@@ -905,6 +905,13 @@ const zhCN = {
         queued: "任务已提交，正在排队生成",
         submitted: "生成任务已提交，正在刷新文章列表。",
       },
+      leaveConfirm: {
+        title: "是否保存为草稿？",
+        content: "当前模版向导已有填写内容。离开前可以保存为草稿，稍后继续编辑。",
+        stay: "继续编辑",
+        discard: "不保存离开",
+        save: "保存草稿",
+      },
     },
   },
   article: {