#5507 "Alert emails through the outbox, gathered for 2 minutes"
(milestone 501). Replaces the in-memory core/alert_burst.py.
- outbox.hold_alert: an alert joins each recipient's held alert email, or
opens one due 2 minutes later (System 156 ruling). A Postgres advisory
lock keeps two alerts at once from opening two windows for one reader.
- email_outbox_events.alert_json (migration 0043) keeps the alert as it
fired, so the email written when the window closes says what it said.
- write_held writes it then, in the reader's zone: the usual alert email
for one alert, the list for several (outbox.alert_words).
- after_settle records on each AlertEvent, once every email carrying it
has settled: email_sent, or email_error naming each reader it didn't
reach and the server's reason.
- A held email survives a restart and goes out when its window closes.
- A refusal of a message's one recipient no longer repeats the address.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
#5465 "One email per burst of alerts". When a switch reboots, every host's
agent-offline rule fires at once and each account got one email per rule.
Alert email now waits 30 s from the first alert: each recipient then gets one
message listing every alert in the window, oldest first, in their own zone
("[Steward] 3 alerts: 2 firing, 1 resolved"). One alert alone keeps its
usual email. Webhooks still post per alert, at once. Every alert's event
records the email's outcome. A burst held when Steward stops is not sent;
the alerts stay on the record and on the Alerts page.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>