Build AI Chief of Staff MVP: auth, mailbox sync, briefings, draft replies

Scaffolds a Next.js app with email/password auth, encrypted IMAP/SMTP/CalDAV
mailbox connections, a background sync job, Claude-generated daily briefings,
and an approve-before-send draft reply flow. Includes a clean design system
(light/dark) and deployment config (systemd unit, credential rotation script).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012o9j9RezxbZVKQMrB7oRLY

CLAUDE.md

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