feat: add HTTP healthcheck endpoint via quarkus-smallrye-health

- pom.xml: add quarkus-smallrye-health dependency.
  Exposes /q/health/live and /q/health/ready endpoints (liveness
  and readiness probes for Quarkus apps).
- Dockerfile: install curl-minimal in the microdnf layer so the
  container has a real HTTP client. quarkus-micro-image is based
  on UBI 9 minimal and doesn't ship with curl by default.
- compose.yaml: healthcheck now hits GET /q/health/live with
  curl -f instead of the previous kill -0 1 (which only proved
  the process was alive, not that the HTTP server was responding).

The next CI run will rebuild the native binary with the health
extension baked in; old images pulled from :latest will keep
working since this is additive.

compose.yaml

@@ -44,9 +44,9 @@ services:
     volumes:
       - shot-crafter-data:/work/data
     healthcheck:
-      # La imagen native es PID 1. kill -0 chequea que sigue vivo
-      # sin mandar señal. Devuelve 0 si existe, 1 si no.
-      test: ["CMD-SHELL", "kill -0 1 || exit 1"]
+      # curl contra /q/health/live (extension quarkus-smallrye-health).
+      # Devuelve 200 si la app esta viva. -f falla si el status != 2xx.
+      test: ["CMD", "curl", "-fsS", "--max-time", "5", "http://localhost:8080/q/health/live"]
       interval: 30s
       timeout: 5s
       retries: 3