Update BaseLayout imports in auth email templates to use the
`@zen/core/email/templates` module alias instead of relative paths,
improving maintainability and consistency across the codebase.
- Fix BaseLayout import paths in auth email templates from
`../../core/...` to `../../../core/...` to match correct
directory depth
- Remove unused `DatabaseError` from db.js exports
- Simplify `sendEmail` by extracting `resolveFrom` and `buildPayload` helpers
- Remove `sendAuthEmail` and `sendAppEmail` exports, keeping only `sendEmail` and `sendBatchEmails`
- Replace hardcoded fallback sender with env-based validation (throws if missing)
- Update `BaseLayout` to resolve `supportEmail` from `ZEN_SUPPORT_EMAIL` env var instead of hardcoded default
- Conditionally render support section only when a support email is available
- Remove verbose JSDoc comments and reduce overall code verbosity
hykocx