## What happened

After applying either the stock `vantablack` or `white` theme, **every GTK4 application segfaults on startup when it runs as a native Wayland client** (the default under Hyprland). I noticed it with Nautilus and Ghostty, but it's any GTK4 app.

Because GTK4 is unusable on Wayland with these themes, affected apps end up forced onto XWayland — which then silently breaks **drag-and-drop into all native-Wayland apps** (browser, editors, chat), since Hyprland does not bridge drops across the X11/Wayland boundary.

## Root cause

The two themes name an icon set that isn't installed:

- `themes/vantablack/icons.theme` → `Yaru-gray`
- `themes/white/icons.theme` → `Yaru-grey`

`yaru-icon-theme` (26.04.5.1ubuntu-1) ships no gray/grey variant, and `manual/43-making-your-own-theme.md` lists the valid options as:

`Yaru Yaru-blue Yaru-dark Yaru-magenta Yaru-olive Yaru-prussiangreen Yaru-purple Yaru-red Yaru-sage Yaru-wartybrown Yaru-yellow`

When the configured icon theme cannot be resolved, GTK4 recurses without bound in its icon-lookup fallback path until the stack overflows. gdb/coredump shows ~52,000 frames inside `libgtk-4.so.1` bottoming out in `g_get_monotonic_time`:

```
#2  g_get_monotonic_time_ns () at /usr/lib/libglib-2.0.so.0
#3  g_get_monotonic_time () at /usr/lib/libglib-2.0.so.0
#4  ??? () at /usr/lib/libgtk-4.so.1
#5  ??? () at /usr/lib/libgtk-4.so.1
#6  ??? () at /usr/lib/libgtk-4.so.1   <- repeats ~52k times
...
#52359  g_application_run () at /usr/lib/libgio-2.0.so.0
```

## Steps to reproduce

1. `omarchy theme set vantablack` (or `white`)
2. Run any GTK4 app as a Wayland client, e.g. `nautilus --new-window` (GTK4 already prefers Wayland under Hyprland; to force it: `GDK_BACKEND=wayland nautilus --new-window`)
3. It segfaults immediately.

Minimal repro independent of Omarchy:

```bash
gsettings set org.gnome.desktop.interface icon-theme Yaru-gray
GDK_BACKEND=wayland nautilus --new-window   # SIGSEGV
```

## Expected

- GTK4 apps start normally when an icon set is missing (ideally falling back to `hicolor`/`Yaru` rather than overflowing the stack).
- The two stock themes reference an installed icon set.

## Actual

`SIGSEGV` (stack overflow) in `libgtk-4.so.1` icon-theme lookup. The crash is renderer-independent — it reproduces with `GSK_RENDERER=cairo`, `LIBGL_ALWAYS_SOFTWARE=1`, and on both GPUs, so it isn't a GPU/dmabuf issue.

## System

- Omarchy `4.0.4-1`
- Hyprland `0.56.2-2`
- gtk4 `1:4.22.4-1`, glib2 `2.88.3-1`
- yaru-icon-theme `26.04.5.1ubuntu-1`
- Kernel `7.2.3-arch1-3`
- AMD Cezanne iGPU + NVIDIA TU117M (crash not GPU-specific)

## Suggested fix

Point both files at an installed icon set. Since no gray/grey variant exists, `Yaru` (the neutral base) is the closest valid value; happy to adjust if another accent is intended. A PR to that effect is incoming.