Email reminders for upcoming interviews and due tasks

[Joun-Mikhail]

Summary

Send opt-in email reminders ahead of interviews and for tasks nearing their due date.

Motivation

The app already tracks scheduled_at and task due_date; surfacing them as reminders closes the loop so users don’t miss anything.

Proposed approach

• A scheduled job (APScheduler or an external cron hitting an authenticated endpoint) that queries due reminders.
• Pluggable email backend (SMTP / Resend / SES) behind a Notifier interface; no-op in test.
• Per-user opt-in + lead time in Settings.

Acceptance criteria

• Configurable lead time (e.g. 1h / 1 day before).
• Idempotent — a reminder is sent at most once.
• Fully covered by tests with a fake notifier.