Harden settler runtime and scaffold tests

test/edge/structure-examples-node-type.edge.test.js

@@ -0,0 +1,11 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const flow = JSON.parse(fs.readFileSync(path.resolve(__dirname, '../../examples/basic.flow.json'), 'utf8'));
+
+test('basic example includes node type settler', () => {
+  const count = flow.filter((n) => n && n.type === 'settler').length;
+  assert.equal(count >= 1, true);
+});