[Feature Request]: Expose progress to front end scripts

### 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 ?

Would it be possible to expose the `useExecutionStore` to scripts outside of comfy's build realm?
Say make it a property of the **app**?
Or perhaps there is already a way to access them stores somehow but I'm too noob to figure this out yet.

I would love to access the progress properties (i.e. **totalNodesToExecute, nodesExecuted, executionProgress**) without the need to rewrite the logic in that store.

Tagging you @huchenlei since you did most of the work on this.

### Proposed workflow

In ideal world it would be so custom node's front-end scripts can do something like:
````javascript
console.log("Progress: " + (app.executionStore.nodesExecuted / app.executionStore.totalNodesToExecute * 100) + "%";
````

### Additional information

Alternatively, if there is a way to access the pinia stores from global space somehow then I would greatly appreciate pointing me in a right direction 🙏