feat: add staff onboarding, password setup and welcome emails

refactor(notifications): remove unused notification orchestrator imports

feat(notifications): add educational notifications

refactor(notifications): update notification cta links to use bridge routing

feat: add custom user symptom support

feat(notifications): replace reset password deeplink with web url

feat(notifications): enhance reset password email with deep link and updated template

feat(email): add Brevo email service with scheduled alerts and notifications

feat(notifications): integrate health assessment and enhance email service

feat(monitoring): add real-time monitoring engine with state management

Initial backend deployment with Docker and Cron jobs