Add health check monitoring

**Summary**: Create comprehensive health check monitoring system that validates application health during and after deployments.

**Acceptance Criteria**:
- [ ] Configurable health check endpoints and criteria
- [ ] Health check execution scheduling and monitoring
- [ ] Health status aggregation and reporting
- [ ] Health check failure detection and alerting
- [ ] Custom health check implementation support
- [ ] Integration with Azure health monitoring services

The issue names no files, tests, or entry points. Start by locating the deployment and monitoring entry points in this Go CLI and reviewing how Azure integrations are organized. Done means covering the listed configuration, scheduling, aggregation, failure alerting, custom checks, and Azure health-monitoring integration criteria.

Written by the indexing model from the issue text.