🔧 chore(ci): move daily thirdparty poll to 06:00 Beijing time

Gitea Actions evaluates cron in UTC, so 22:00 UTC lands at 06:00 the next
day in UTC+8. The previous 03:17 UTC fired at 11:17 Beijing time, in the
middle of the working day.

The schedule triggers Prepare, and update-thirdparty-skills runs off its
workflow_run completion, so moving Prepare moves the whole chain.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitea/workflows/prepare.yml

@@ -14,8 +14,8 @@ on:
       - main
   workflow_dispatch:
   schedule:
-    # thirdparty 快照每日轮询：Prepare 定时成功后，update-thirdparty-skills 通过 workflow_run 触发。
-    - cron: "17 3 * * *"
+    # 北京时间（UTC+8）每日 06:00；Prepare 成功后由 workflow_run 触发 thirdparty 快照更新。
+    - cron: "0 22 * * *"
 
 concurrency:
   group: prepare-${{ github.repository }}