[Bug]: v0.8.3 Debian package misses libxkbcommon-x11 runtime dependency, preventing GUI startup

### Pre-flight checklist
- [x] Searched existing issues for `libxkbcommon`, `xkbcommon`, missing Linux dependencies, and shared-library errors; no matching issue found.
- [x] Using the latest release at the time of reporting: v0.8.3.
- Logi Options+ conflict: not applicable to this dynamic-loader failure on Linux.

### Which part of OpenLogi?
GUI (desktop app) / Debian package

### OpenLogi version
0.8.3 (`openlogi-v0.8.3-linux-amd64.deb`)

### Operating system
Linux — Ubuntu 26.04.1 LTS (Resolute Raccoon), amd64

### Device model and connection
Logitech MX Master 3S, Bluetooth (direct, no receiver). The background agent and CLI successfully detect the mouse.

### Affected area(s)
Other: installation and GUI startup

### What happened?
After installing the release `.deb`, clicking the application launcher did not open the GUI. Running `openlogi-desktop` from a terminal revealed a missing runtime library:

```text
openlogi-desktop: error while loading shared libraries: libxkbcommon-x11.so.0: cannot open shared object file: No such file or directory
```

The agent started successfully with `systemctl --user enable --now openlogi-agent.service`, and the `openlogi` CLI detected the mouse, so the installation appeared successful until launching the GUI.

Expected: the Debian package should declare the runtime dependencies needed by the included desktop binary, and the installation instructions should explain how to install/resolve them.

### Steps to reproduce
1. On Ubuntu amd64 without `libxkbcommon-x11-0` installed, install `openlogi-v0.8.3-linux-amd64.deb`. I initially installed it by clicking the file, then also ran the README's `sudo dpkg -i openlogi-*.deb` command.
2. Enable the user agent with `systemctl --user enable --now openlogi-agent.service`.
3. Click the OpenLogi application launcher: no GUI appears.
4. Run `openlogi-desktop` in a terminal: the loader prints the error above.

### Diagnostics / logs
Before installing the missing library:

```text
$ ldd /usr/bin/openlogi-desktop | rg 'not found'
libxkbcommon-x11.so.0 => not found
```

The installed package has an empty Depends field:

```text
$ dpkg-query -W -f='${Package} ${Version}\nDepends: ${Depends}\n' openlogi
openlogi 0.8.3
Depends:
```

The GUI could not launch to provide an About-window diagnostics report at the time of failure.

### Workaround and suggested fix
Install the missing runtime package:

```bash
sudo apt install libxkbcommon-x11-0
openlogi-desktop
```

After installing it, `ldd` resolves `libxkbcommon-x11.so.0` and reports no missing libraries. Full GUI functionality has not been independently verified for this report.

Please consider declaring `libxkbcommon-x11-0` (and checking the other runtime dependencies of the shipped binaries) in the `.deb` metadata. The README currently recommends `sudo dpkg -i openlogi-*.deb`; documenting a dependency-resolving installation command such as `sudo apt install ./openlogi-v0.8.3-linux-amd64.deb` would also help once the metadata is fixed. A troubleshooting note for existing packages would be useful in the meantime.

Start with the Debian package metadata for openlogi-v0.8.3-linux-amd64.deb and the README installation instructions. Run ldd /usr/bin/openlogi-desktop | rg 'not found' to check the shipped binary, then verify that the package Depends field includes libxkbcommon-x11-0 and that apt install ./openlogi-v0.8.3-linux-amd64.deb resolves installation. Done means the GUI launches on Ubuntu amd64 without the reported missing-library error.

Written by the indexing model from the issue text.