fix: persist service host port; demo-data scope for telemetry

Public URLs were ephemeral: every restart/redeploy rebound a random host
port, so endpoint links rotted. Persist published_port on the service and
prefer it for replica 0 on create. If the port is taken, fall back to
ephemeral and repersist the new assignment. Post-start the binding is
verified — Docker Desktop accepts a conflicting publish silently, which
previously left services running with no endpoint at all.

demo-data.ts gains the required scope field for HostMonitoring (CI fix).

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/backend/internal/api/services.go

@@ -520,7 +520,9 @@ func handleUpdateService(c *gin.Context) {
 				}
 				ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
 				defer cancel()
-				_, _ = engine.ReconcileService(ctx, spec)
+				if state, err := engine.ReconcileService(ctx, spec); err == nil && state != nil {
+					persistPublishedPort(db.(*database.DB), serviceCopy.ID, state.Ports)
+				}
 			}()
 		}
 	}