Configure internal management server on port 9090 with Prometheus metrics

[Copilot]

Separates the actuator/management plane onto port 9090 (internal-only) away from the public API on port 8080, and adds Prometheus metrics export support.

Changes

• application.yml — sets management.server.port: 9090, expands exposed endpoints to health, info, metrics, prometheus, and enables Prometheus export:

  management:
    server:
      port: 9090
    endpoints:
      web:
        exposure:
          include: health,info,metrics,prometheus
    metrics:
      export:
        prometheus:
          enabled: true

• pom.xml — adds micrometer-registry-prometheus (version managed by Spring Boot BOM)
• Dockerfile — adds EXPOSE 9090
• docker-compose.yml — binds management port as 127.0.0.1:9090:9090 to prevent public exposure

SecurityConfig note

No changes needed — management.server.port spawns a separate servlet context; the existing SecurityFilterChain scoped to port 8080 does not apply to it.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.