Fix Wayland/KDE6 isolation

[LanceHaverkamp]

Key Improvements Made:

XDG Path Redirection: Added XDG_CONFIG_HOME and XDG_DATA_HOME. This prevents the "locked database" errors because each instance now looks for its config in ~/MEGA/InstanceName/.config instead of your real ~/.config.

Platform Forcing: Added QT_QPA_PLATFORM=xcb. This tells the MEGA (Qt) app to use XWayland, which effectively disables the Wayland compositor's ability to "smartly" group these into a single process.

Path Scrubbing: In the launch loop, I added ${d%/} to ensure the path doesn't end in a double slash, which can occasionally trip up certain file-watchers in Linux.

Zenity Fix: I fixed a small typo in your original script where the first zenity call had the word zenity repeated inside the text string