[Bug]: GUI cannot delete per-application profile on Linux/Niri (0.8.3)

### Pre-flight checklist

- [x] I searched [existing issues](https://github.com/AprilNEA/OpenLogi/issues?q=is%3Aissue) and this is not a duplicate.
- [x] I am on the [latest release](https://github.com/AprilNEA/OpenLogi/releases/latest) or a recent `master` build.
- [x] I quit **Logi Options+** before running OpenLogi (the two apps fight over HID++ access and only one can own a receiver at a time).

### Which part of OpenLogi?

GUI (desktop app)

### OpenLogi version

0.8.3-1 (official Arch package); also reproduced with 0.8.1-1

### Operating system

Linux

### OS version & architecture

CachyOS (Arch Linux), x86_64; Niri / Wayland; kernel 7.2.0-1-cachyos

### Device model

Logitech MX Master 3, receiver connection

### How is the device connected?

Other / not sure

### Affected area(s)

- [ ] Device discovery / detection
- [ ] Button remapping
- [ ] DPI control
- [ ] SmartShift
- [x] Per-application profiles
- [ ] Battery status
- [x] Settings / configuration (TOML)
- [ ] Auto-update
- [ ] Menu bar / tray
- [ ] Other

### What happened?

Clicking the GUI delete action for a per-application profile has no visible effect, and the profile is not removed. The original example was QMPlay2, with thumb-wheel up/down mapped to VolumeUp/VolumeDown.

Expected: remove the selected application profile from the UI and persist the deletion, or show an actionable error if it fails.

The problem occurred on 0.8.1 and still occurs after upgrading to the official 0.8.3 Linux x86_64 Arch package and restarting the desktop UI and background agent.

Workaround: backing up ~/.config/openlogi/config.toml and manually removing the QMPlay2 per_app_bindings table successfully removed the configuration. The file and parent directory are owned by the current user and writable. This report concerns the GUI deletion operation, not deleting QMPlay2 itself. The root cause has not been identified.

Logi Options+ is not running on this Linux system.

### Steps to reproduce

1. Open OpenLogi on Niri/Wayland with an existing per-application profile.
2. Select the application profile (original example: QMPlay2 with thumb-wheel VolumeUp/VolumeDown bindings).
3. Click the GUI delete action for that profile.
4. Observe no visible response and no profile deletion.
5. Retry after upgrading from 0.8.1 to 0.8.3 and restarting the UI and agent: the GUI issue persists.

### Diagnostics report

```markdown

```

### `openlogi list` output

```text

```

### Logs

```shell

```

### macOS permissions (if applicable)

- [x] OpenLogi has **Accessibility** permission (needed to remap buttons via the event tap).
- [x] OpenLogi has **Input Monitoring** permission (needed for Bluetooth-direct devices and capture).

Start by reproducing the GUI deletion failure with an existing per-application profile on Linux/Niri/Wayland, then trace the per-app profile delete action and its configuration persistence path. Use ~/.config/openlogi/config.toml to verify whether the profile is removed; done means the selected profile disappears from the UI and config, or an actionable error is shown.

Written by the indexing model from the issue text.