Update the runtime to the latest version

This application relies on an outdated runtime that has been marked as end-of-life (EOL).

Software stores (GNOME Software, KDE Discovery, Bazaar, etc.) usually warn about EOL status and (depending on the software stores) discourage people from using EOL applications.

Please consider updating the runtime to the latest version.

Thank you.

```
LC_ALL=C flatpak remote-info flathub --system org.freedesktop.Platform//23.08
End-of-life: org.freedesktop.Platform 23.08 is no longer receiving fixes and security updates. Please update to a supported runtime version.
Date: 2025-09-29 15:36:17 +0000
```

Start by locating the Flatpak metadata that declares org.freedesktop.Platform//23.08, then use the provided flatpak remote-info command to check the available supported runtime. Update the runtime reference to a supported version and verify that the application no longer reports the 23.08 end-of-life warning.

Written by the indexing model from the issue text.