**Problem**: stock-close-report didn't trigger on the day of the timezone switch from UTC to Asia/Shanghai. No error messages, none at all.

**Cause**: lastRunAt stored a UTC timestamp. After the timezone switch, the scheduler mistakenly concluded "already ran today" and skipped it. The system kept running normally — just running on wrong logic.

**Solution**: Rewrote the timezone declaration for all cron jobs, standardized to `Asia/Shanghai`. Monitored the next trigger time to confirm execution.

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**Principle**: "No errors" ≠ "running correctly." Critical tasks need result validation — not just checking whether the task ran, but whether the output actually arrived. Silent failures are more dangerous than errors.