### Summary

`omarchy install gaming battlenet` gives the user no feedback for several minutes. The script prints "Launching the Battle.net setup wizard. Click through it normally…" and detaches `umu-run` with `setsid -f`, then exits. Before any window appears, `umu-run` silently downloads:

1. GE-Proton (~530 MB) — if not already cached
2. the steamrt4 runtime (~hundreds of MB)

On a typical connection this takes some time: no window, no progress bar, no terminal output. Only `tail /tmp/omarchy-battlenet-installer.log` shows what is happening. The result looks exactly like a hung install (I first assumed Battle.net was broken).

### Steps to reproduce

1. On a machine without `~/.local/share/Steam/compatibilitytools.d/GE-Proton*` and without the umu steamrt4 cache, run:
   ```
   omarchy install gaming battlenet
   ```
2. The script exits after printing the log path.
3. Nothing appears on screen until both downloads finish and the Battle.net setup wizard finally opens.

### Expected

Some visible feedback while the runtime downloads happen, e.g. the detached `umu-run` running in a visible (floating) terminal, or the script staying in the foreground and showing progress (curl-style or a `gum` spinner) until the wizard is up.

### Current code

`/usr/share/omarchy/bin/omarchy-install-gaming-battlenet`:

```bash
setsid -f sh -c "umu-run '$installer' >'$log' 2>&1" </dev/null >/dev/null 2>&1
echo "Installer log: $log"
```