通知アラートシステム

I want to set up automated notifications on my Mac. Please create:

1. File monitoring:
   - Alert when any file is added to ~/Downloads
   - Alert when ~/Documents/Important changes

2. System alerts:
   - Notify if disk usage exceeds 80%
   - Alert when a specific process stops

3. Scheduled reminders:
   - Daily standup reminder at 9:45 AM
   - Weekly backup reminder on Sundays

Create the scripts and launchd configurations. Save to ~/Scripts/notifications/