[Feature Request]: Provide progress bar API

### Is there an existing issue for this?

- [x] I have searched the existing issues and checked the recent builds/commits

### What would your feature do ?

This feature would provide an API for extensions to display a progress bar. It would be similar to the [toast feature](https://github.com/Comfy-Org/ComfyUI_frontend/blob/main/README.md#extension-api-toast), which has been well recieved and improved many extensions. The component would be the [PrimeVue progress bar](https://primevue.org/progressbar/#dynamic).

In addition to custom nodes, the progress bar could also be used by ComfyUI-Manager and the desktop app.

### Proposed workflow

1. Register a progress bar:

```typescript
app.extensionManager.progressBar.registerProgressBar({
value: () => myProgressStatus,
pollInterval: 50,
mode: 'determinate',
label: `Downloading ${customNodeName}`,
onComplete: () => {
console.log('Download complete')
},
dismissable: false,
position: 'top',
attrs: {
class: 'bg-blue-500 w-50'
}
})
```

2. The progress bar displays in a position and style familiar to user, as this feature is used by other extensions and components:

https://github.com/user-attachments/assets/fe893aa6-f7b6-4605-a5bd-43b95886bdd6

### Additional information

_No response_

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