System cron
once daily (seeds)
every minute
(schedule:run)
cron_seed_daily.php
one job per mailbox, per client
cron_mail_seed_daily.php
one job per client
cron_queue
master DB
cron_mail_send
master DB
Laravel scheduler
app:process-email-queue — every 10 min, 5 jobs
app:send-daily-email-summary — every 5 min, 13:00–18:00
Both commands claim a batch, mark it done or failed, and re-open completed fetch jobs as pending so a mailbox is polled repeatedly through the day.