Recursion bug due to module.build() connection tracing

### Describe the bug

With some module miswirings we can get a `StackOverflow` due to infinite recursion.

### To Reproduce

Run the following test:

```
import 'package:rohd/rohd.dart';
import 'package:test/test.dart';

class EmptyModule extends Module {
EmptyModule({super.name});
}

class RecursivePortCheckRepro extends Module {
RecursivePortCheckRepro() : super(name: 'top') {
final driver = Logic();
final topA = addInput('a', driver);

final child = EmptyModule(name: 'child');
final childA = child.addInput('a', topA);

// The `and()` avoids Logic's immediate direct self-connection rejection
// while closing the signal graph.
driver <= childA.and();
}
}

void main() {
test('discovers a cyclic hierarchy', () async {
await expectLater(
RecursivePortCheckRepro().build(),
throwsA(isA()),
);
});
}
```

### Expected behavior

An error reported on the bad connection in the parent to a child `Logic`.

### Actual behavior

`StackOverflow`

### Additional: Dart SDK info

_No response_

### Additional: pubspec.yaml

```yaml

```

### Additional: Context

The simplest fix would look like:
```
void _checkPortConnectionsRecursively({
Set? visited,
}) {
final marked = visited ?? {};

// Mark before descending. This breaks cycles such as top -> child -> top.
if (!marked.add(this)) {
return;
}

_checkPortConnections();

for (final subModule in _subModules) {
subModule._checkPortConnectionsRecursively(visited: marked);
}
}
```

Start at Module.build() and the _checkPortConnectionsRecursively entry point, then reproduce the cycle with the test case shown in the issue. Add a regression test for the cyclic hierarchy and verify that build() reports InvalidHierarchyException for the bad parent-to-child connection instead of StackOverflow.

Written by the indexing model from the issue text.