Post-deployment monitoring and alerting setup

## Description

Currently, post-deployment validation runs health checks but does not configure ongoing monitoring. The manifesto envisions closing the loop between observability and action.

## Scope

1. **Azure Monitor integration** — Auto-configure alert rules for deployed resources (availability, error rates, response times).
2. **Application Insights** — Auto-instrument web apps and function apps with Application Insights.
3. **Dashboard generation** — Create an Azure Dashboard with key metrics for the deployment.
4. **Alert action groups** — Configure notification channels (email, Teams, PagerDuty).

## Acceptance Criteria

- [ ] Deployed resources have Azure Monitor alerts configured.
- [ ] Web apps/functions have Application Insights instrumented.
- [ ] Azure Dashboard created for the deployment.