Qt/GTK themes generated by matugen not applying

### Compositor

MangoWC (dwl)

### Distribution

Arch Linux

### If Other, please specify

_No response_

### Select your Installation Method

Distro Packaging

### Was this your original Installation method?

Yes

### If no, specify

_No response_

### dms doctor -vC

Click to expand
- AVIF, HEIF, JXL support
- [ok] Terminal: kitty, foot
- [ok] Network: NetworkManager
- NetworkManager present. Using NM API.
- [ok] matugen: Installed
- Dynamic theming
- [ok] dgop: Installed
- System monitoring
- [warn] cava: Missing
- Audio visualizer
- [info] khal: Not installed
- Calendar events
- [info] danksearch: Not installed
- File search
- [info] dankcalendar: Not installed
- Calendar app
- [info] fprintd: Not installed
- Fingerprint auth

**Config Files**
- [ok] settings.json: Present
- /home/flyshine/.config/DankMaterialShell/settings.json
- [info] clsettings.json: Not yet created
- /home/flyshine/.config/DankMaterialShell/clsettings.json
- [info] plugin_settings.json: Not yet created
- /home/flyshine/.config/DankMaterialShell/plugin_settings.json
- [ok] session.json: Present
- /home/flyshine/.local/state/DankMaterialShell/session.json
- [ok] dms-colors.json: Present
- /home/flyshine/.cache/DankMaterialShell/dms-colors.json

**Services**
- [warn] dms.service: Disabled
- [info] greetd: Not installed
- Optional greeter service

**Environment**
- [info] QT_QPA_PLATFORMTHEME: Not set
- [info] QS_ICON_THEME: Not set
- [warn] XDG_MENU_PREFIX: Not set
- Dolphin file associations and 'Open with…' dialog may be empty. Set XDG_MENU_PREFIX=plasma- in your compositor's environment block.

**Fonts**
- [warn] Normal Font: 'FiraCode Nerd Font' not found
- Font is not registered. Try running 'fc-cache -fv' or install the font.
- [warn] Monospace Font: 'FiraCode Nerd Font' not found
- Font is not registered. Try running 'fc-cache -fv' or install the font.

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**Summary:** 0 error(s), 9 warning(s), 25 ok

### Description

Themes made by matugen aren't applying, for example on Thunar it's still the same theme; however it works on another app, specifically Zed editor

### Expected Behavior

The themes would have been applied instead of being the default

### Steps to Reproduce

1. Navigate to system app theming on settings
2. Click apply qt/gtk colors
3. Take a look at qt/gtk apps

### Error Messages/Logs

_No response_

### Screenshots/Recordings

_No response_

Start at the System App Theming settings entry point and reproduce the Qt/GTK colors flow on Arch Linux with MangoWC. Compare a Thunar or other Qt/GTK application that remains unchanged with Zed, where theming works, and inspect the dms doctor output for relevant environment or configuration differences. Done means applying the setting changes the affected Qt/GTK application themes.

Written by the indexing model from the issue text.