- stages/09-desktop.sh: new autostart section — copies .desktop files
for Firefox, Ghostty, Nextcloud, Obsidian, Thunderbird into
~/.config/autostart/ so they launch at login
- stages/12-other-apps.sh: add Thunderbird, VirtualBox (Fedora via
RPM Fusion), Zoom (via Flatpak); fallback Signal to Flatpak
(no official RPM repo); remove FreeRDP (not needed on Fedora)