feat: sample recent business events

internal/observability/metrics_test.go

@@ -123,6 +123,7 @@ func TestBusinessSnapshotKeepsLastGoodStateOnFailure(t *testing.T) {
 		DeliveryOldestAgeSeconds: 8.25,
 		WorkflowStates:           map[string]uint64{"RUNNING": 1},
 		WorkflowOldestAgeSeconds: 4.75,
+		RecentEvents:             map[string]uint64{"task.accepted": 5},
 		Truncated:                true,
 	}, started, nil)
 	first := r.Render()
@@ -130,6 +131,7 @@ func TestBusinessSnapshotKeepsLastGoodStateOnFailure(t *testing.T) {
 		`orbit_pulse_tasks_state{state="WAITING"} 3`,
 		`orbit_result_deliveries_state{state="PENDING"} 2`,
 		`orbit_weave_workflows_state{state="RUNNING"} 1`,
+		`orbit_business_events_recent{event="task.accepted"} 5`,
 		"orbit_pulse_tasks_oldest_age_seconds 12.5",
 		"orbit_business_snapshot_truncated 1",
 		`orbit_business_snapshot_total{outcome="success"} 1`,