Wire real email provider + finish guest_comms schedule/win_back gaps (TEL-7)

[telivity-otaip]

Summary

Completes TEL-7 guest communications gaps: real email delivery when a provider is configured, scheduled pre-arrival/day-of runs, win-back generation, and honoring postStayDelayHours.

Changes

Email provider wiring

• Document SENDGRID_* and SMTP_* env vars in .env.example and .env.production.example
• Existing send path unchanged: approve → GuestCommunicationAgent.execute() → EmailService (SendGrid → Mailgun → SES → SMTP)

Scheduled guest_comms/run

• Add 0 7 * * * daily cron to agent graph and docs/operations/cron.md
• Scheduled/manual runs now draft: pre-arrival, day-of, delayed post-stay, and win-back

postStayDelayHours

• Checkout events skip immediate post-stay when delay has not elapsed
• Daily scheduled run picks up checked-out reservations once postStayDelayHours has passed

win_back

• Scheduled runs generate win-back drafts for guests whose departure date is exactly winBackDays ago
• Templates use actual days_since instead of a hardcoded 90

Acceptance

• Approving a pending decision sends real email when SENDGRID_* or SMTP_* is set
• Pre-arrival/day-of can be produced via POST /agents/:propertyId/guest_comms/run?triggeredBy=schedule or manual Run

Testing

• vitest run src/modules/agent/guest-comms/ src/modules/agent/agent-graph.spec.ts — 48 tests passing

Linear Issue: TEL-7