Bug: setState_Net().done() on existing schematic netport clears net instead of updating it

## Summary

When using the EasyEDA bridge to update an existing schematic `netport` component, calling `toAsync().setState_Net(newNet).done()` did not update the net name to `newNet`. Instead, the net became an empty string (`""`) when read back with `getState_Net()`.

Creating a new net port with `sch_PrimitiveComponent.createNetPort('BI', newNet, x, y, rotation, mirror)` works correctly and immediately returns the expected net name.

## Environment

- Skill repository/version: `easyeda-api-skill` v1.1.3
- Bridge: `scripts/bridge-server.mjs`
- EasyEDA context: schematic page, existing `netport` primitives
- Host OS: Windows
- Node.js: v24.14.1

## Reproduction

1. Open a schematic page containing an existing net port, for example one with net `RGB_DB2`.
2. Fetch that existing net port with `sch_PrimitiveComponent.get(id)` or from `sch_PrimitiveComponent.getAll()`.
3. Try to update its net:

```js
const port = await eda.sch_PrimitiveComponent.get('existing-netport-id');
const asyncPort = port.toAsync();
asyncPort.setState_Net('GPIO1_C5_d');
await asyncPort.done();

const check = await eda.sch_PrimitiveComponent.get('existing-netport-id');
return check.getState_Net();
```

## Expected behavior

`check.getState_Net()` should return:

```text
GPIO1_C5_d
```

## Actual behavior

`check.getState_Net()` returned an empty string:

```text

```

In my test, multiple existing `netport` primitives with original net names such as `RGB_DB2`, `RGB_DB3`, etc. were changed to blank nets after attempting `setState_Net(...).done()`.

## Workaround

Deleting the original net port and recreating it at the same coordinates works:

```js
await eda.sch_PrimitiveComponent.delete('existing-netport-id');
const created = await eda.sch_PrimitiveComponent.createNetPort(
'BI',
'GPIO1_C5_d',
x,
y,
rotation,
mirror
);
return created.getState_Net();
```

This returns the expected new net name.

## Notes

The issue was observed while replacing `RGB_*` net labels with the corresponding `GPIO*` names from U1 pin descriptions. The replacement only became reliable after deleting and recreating the net ports.