How to read the docs

The documentation catalog is the left nav. Start with this page, then the canonical data model and repository structure.

Working rule

MailMessage is the logical message. MessageInstance is the provider/account occurrence. Cardinality is 1:N.

PostgreSQL hosting, required environment variables, and the migration runner are in persistence and environments and ADR 0002. Application sessions (signed HTTP-only cookie, no external IdP) are in application authentication and ADR 0005. Provider token ciphertext and key separation are in token encryption and ADR 0004.

Jira project MAIL is the implementation plan. Architecture decisions that change hosting or queue technology belong in docs/decisions/.