Playground compilation shows no progress feedback during ZK proof generation

### Packages versions

miden-base: latest
playground: web (playground.miden.xyz)

### Bug description

During tutorial compilation steps, the UI shows a generic spinning loader
with no progress indicator or estimated time. Compilation can take 1-3 minutes
which is confusing for new users who don't know if it's still working or frozen.

### How can this be reproduced?

1. Open playground.miden.xyz
2. Create a new script (Account Component or Note Script)
3. Click the Compile button
4. Observe the loading state — only a spinner shown, no progress or ETA

### Relevant log output

```shell

```

The issue is in the playground web UI (playground.miden.xyz). Look for the compilation button handler and the component that displays the spinner. Investigate how the ZK proof generation progress can be monitored from the backend (miden-base) and exposed to the frontend. Check existing API calls and consider adding a progress event stream or polling endpoint. The goal is to replace the generic spinner with a progress bar or percentage indicator.

Escrito por el modelo de indexación a partir del texto del issue.