[Feature]: Add `--no-popup` flag to prevent app from popping up on file reload

I’ve noticed that the current behavior of the app can be disruptive in certain workflows.

### Current Behavior:

When file changes are detected, the application restarts and pops up to the front of the screen. This happens every time a reload occurs.

### Problem:

While this behavior may be helpful for quick prototyping, it becomes annoying or disruptive when working on something serious that requires multiple rounds of edits. The frequent app pop-ups interrupt focus and can interfere with multitasking (especially when writing code or debugging).

### Suggested Solution:

Introduce a new CLI parameter: `--no-popup`.

* When this flag is passed, the application should **reload in the background** without changing its current state (i.e., stay minimized or in the background if it was already).
* This would maintain the reload-on-change functionality without stealing focus from the user every time.

### Benefit:

This would make the development experience much smoother, especially during longer dev sessions, without removing the helpful hot-reload feature.

The issue names no files, tests, or entry points; start by locating CLI argument parsing and the file-reload/window-focus path. Done means the new flag is accepted and reloads leave the application minimized or in the background without stealing focus, while existing reload behavior remains unchanged.

Written by the indexing model from the issue text.