Glitches on the border of quick control panel when blur is turned on

### Compositor

Niri

### 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
## DMS Doctor Report

**System**
- [ok] Operating System: Arch Linux
- ID: arch, Version: rolling, Arch: amd64
- [ok] Architecture: amd64
- [ok] Display Server: Wayland
- WAYLAND_DISPLAY=wayland-1

**Versions**
- [ok] DMS CLI: dms v1.5.3
- /usr/bin/dms
- [ok] Quickshell: Quickshell 0.3.1 (revision , distributed by Arch Linux)
- /usr/bin/qs
- [ok] DMS Shell: v1.5.3
- /usr/share/quickshell/dms

**Installation**
- [ok] DMS Configuration: Found
- /usr/share/quickshell/dms
- [ok] shell.qml: Present
- /usr/share/quickshell/dms/shell.qml
- [info] Install Type: System package
- /usr/share/quickshell/dms

**Compositor**
- [ok] niri: 26.04
- /usr/bin/niri
- [info] Active: niri
- [ok] Background Blur: Supported
- Compositor supports ext-background-effect-v1

**Quickshell Features**
- [ok] Polkit: Available
- Authentication prompts
- [ok] IdleMonitor: Available
- Idle detection
- [ok] IdleInhibitor: Available
- Prevent idle/sleep
- [ok] ShortcutInhibitor: Available
- Allow shortcut management (niri)
- [ok] BackgroundBlur: Available
- Background blur API support in Quickshell

**Optional Features**
- [ok] accountsservice: Available
- User accounts
- [ok] power-profiles-daemon: Available
- Power profile management
- [ok] logind: Available
- Session management
- [warn] cups-pk-helper: Not available (install cups-pk-helper)
- Printer management
- [info] I2C/DDC: No monitors detected
- External monitor brightness control
- [ok] qt6-imageformats: Installed (1 formats)
- Formats: GIF (/usr/lib/qt6/plugins/imageformats:/usr/lib64/qt6/plugins/imageformats)
- [warn] kimageformats: Not installed
- AVIF, HEIF, JXL support
- [ok] Terminal: kitty
- [ok] Network: iwd
- iwd detected without NM/ConnMan. Using iwd API.
- [ok] matugen: Installed
- Dynamic theming
- [ok] dgop: Installed
- System monitoring
- [ok] cava: Installed
- 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/fan/.config/DankMaterialShell/settings.json
- [info] clsettings.json: Not yet created
- /home/fan/.config/DankMaterialShell/clsettings.json
- [info] plugin_settings.json: Not yet created
- /home/fan/.config/DankMaterialShell/plugin_settings.json
- [ok] session.json: Present
- /home/fan/.local/state/DankMaterialShell/session.json
- [ok] dms-colors.json: Present
- /home/fan/.cache/DankMaterialShell/dms-colors.json

**Services**
- [ok] dms.service: enabled, active
- [info] greetd: Not installed
- Optional greeter service

**Environment**
- [info] QT_QPA_PLATFORMTHEME: qt6ct
- [info] QS_ICON_THEME: Not set
- [info] XDG_MENU_PREFIX: Not set

**Fonts**
- [ok] Normal Font: Inter Display Medium
- Available
- [ok] Monospace Font: Fira Code Retina
- Available

---
**Summary:** 0 error(s), 2 warning(s), 30 ok

### Description

As stated, and this issue persists in xray or non-xray (the default) mode

The three pics above are non-xray, xray and blur-off modes respectively (it is also curious to me that it seems the jagged edges having different colors in non-xray and in xray modes).

### Expected Behavior

I would expect a more smooth border rendered on the border.

### Steps to Reproduce

Turn on the blur option in dms settings and then invoke the quick control panel (and look closely enough).

### Error Messages/Logs

_No response_

### Screenshots/Recordings

_No response_

Start by reproducing the jagged quick control panel border with blur enabled, comparing non-xray, xray, and blur-off modes on the reported Arch Linux and niri setup. Trace the quick control panel and its blur setting first; done means the panel border renders smoothly and consistently across those modes.

Written by the indexing model from the issue text.