`group` widgets ignore horizontal wrapping

**Describe the bug**

When using `ui.group()` inside something like `ui.horizontal_wrapped()`, the widgets seem to ignore wrapping and just keep going well past screen boundaries. I went crazy trying to figure out why my UI was overflowing, until I removed the group and it started wrapping as expected.

**To Reproduce**

I put together this simple sample with eframe that triggers the issue:

```rust
#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
use eframe::egui;

#[derive(Default)]
struct DummyApp;

impl eframe::App for DummyApp {
fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
egui::CentralPanel::default().show(ctx, | ui | {
ui.horizontal_wrapped(| ui | {
for n in 0..500 {
ui.group(| ui | {
ui.strong(format!("Number {n}"));
});
}
});
});
}
}
fn main() {
let app = DummyApp::default();
let native_options = eframe::NativeOptions::default();

eframe::run_native("wrap_test", native_options, Box::new(|_| Box::new(app)));
}
```

**Expected behavior**

The widgets don't overflow, and they keep going on a new row.

Screenshots

- UI goes off-screen.


---

- Wraps as expected without the group


**Desktop (please complete the following information):**
- OS: Windows
- Version: 10

Let me know if anything else is needed here :)

Start by running the minimal eframe example from the issue and compare ui.group() with the same widgets directly inside ui.horizontal_wrapped(). Trace how these two entry points determine available width and wrapping; done means grouped widgets stay within the panel and continue on new rows.

Written by the indexing model from the issue text.