ci: move DingTalk notify cron off the top of the hour

Change schedule from '0 * * * *' to '17 * * * *'. Top-of-hour is the
most congested slot for GitHub's scheduler and is prone to delays and
dropped runs; an off-peak minute is more reliable.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GRCZ4DdNpsyakwmgRHQLW9

.github/workflows/dingtalk-notify.yml

@@ -4,8 +4,9 @@ name: DingTalk notify on new issues/PRs
 # push a notification to the DingTalk robot.
 on:
   schedule:
-    # At minute 0 of every hour (UTC). GitHub scheduled runs may be delayed a few minutes.
-    - cron: '0 * * * *'
+    # At minute 17 of every hour (UTC). Avoid the top of the hour, which is the
+    # most congested slot for GitHub's scheduler and is more likely to be delayed/dropped.
+    - cron: '17 * * * *'
   workflow_dispatch:
     inputs:
       window_minutes: