fix: migration must update existing ask LINK record (backup old chatgpt link)

Prod had an old ask link (LINK → chatgpt.com, id=235). get_or_create
would leave it as LINK, so go/ask/问题 would redirect to chatgpt instead
of sending to Discord. Switch to update_or_create and back up the old
chatgpt link to alias ask-chatgpt.

links/migrations/0053_ask_as_action_link.py

@@ -15,7 +15,19 @@ DISCORD_BOT_ID = '1467845106831855796'
 
 def create_ask_action_link(apps, schema_editor):
     Link = apps.get_model('links', 'Link')
-    Link.objects.get_or_create(
+    # 若旧 ask 是 LINK 类型（如指向 chatgpt 的快速提问链接），先备份到 ask-chatgpt
+    old = Link.objects.filter(alias='ask').first()
+    if old and old.link_type == 'LINK' and old.original_url:
+        if not Link.objects.filter(alias='ask-chatgpt').exists():
+            Link.objects.create(
+                alias='ask-chatgpt',
+                link_type='LINK',
+                original_url=old.original_url,
+                description=(old.description or 'Quick ask chatgpt') + ' (原 ask 备份)',
+            )
+    # update_or_create：生产库可能已有 ask 记录（旧版可能是 LINK 类型），
+    # 必须更新为 ACTION 类型 + discord_send 配置，否则 go/ask/问题 会走 LINK 分支失败。
+    Link.objects.update_or_create(
         alias='ask',
         defaults={
             'link_type': 'ACTION',
@@ -31,6 +43,7 @@ def create_ask_action_link(apps, schema_editor):
 def remove_ask_action_link(apps, schema_editor):
     Link = apps.get_model('links', 'Link')
     Link.objects.filter(alias='ask', link_type='ACTION').delete()
+    Link.objects.filter(alias='ask-chatgpt', description__endswith='(原 ask 备份)').delete()
 
 
 class Migration(migrations.Migration):