Drop the backup and restore scripts: setup.sh only

Files and app logins move across by hand, so archiving and unpacking a home
directory isn't this repo's job any more. setup.sh installs the machine and
stops there.

Two things restore.sh used to cover, kept where they still matter: the
post-reboot `sudo flatpak update` that fetches the NVIDIA GL runtime (Flatpak
can only match it to a loaded driver, so it can't happen during setup), and the
notes on which dotfiles not to copy over from Fedora. The server-marvin mount is
now optional — press Enter at the prompt to skip it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

flatpaks.txt

@@ -1,6 +1,6 @@
 # Flathub apps installed system-wide by scripts/setup.sh — one ID per line, '#' comments.
 # Picked from everything installed on the Bazzite box (scanned 2026-09-21, chosen 2026-09-23).
-# Restoring ~/.var/app brings each app's data back with it (logins, profiles, saves).
+# Copying ~/.var/app/<app-id> over from the old install brings that app's logins and settings.
 # Removing a line doesn't uninstall the app; `flatpak uninstall <id>` it once by hand.
 
 # -- Internet / chat --
@@ -46,7 +46,7 @@ net.wz2100.wz2100
 
 # ---------------------------------------------------------------------------------------
 # Installed on Bazzite, deliberately left behind. Uncomment to bring one back —
-# its data is still in the backup's home.tar.zst under .var/app/<id>.
+# copy its ~/.var/app/<id> folder across from the old install to keep its settings.
 #
 # com.github.IsmaelMartinez.teams_for_linux   # Teams
 # com.ktechpit.whatsie                        # WhatsApp
@@ -61,6 +61,6 @@ net.wz2100.wz2100
 # io.podman_desktop.PodmanDesktop
 # org.gnome.Calculator                        # Ubuntu has its own
 # net.longturn.freeciv21
-# org.develz.Crawl                            # ~/.crawl saves are still in the backup
+# org.develz.Crawl                            # saves live in ~/.crawl
 # net.sourceforge.atanks
 # org.frozen_bubble.frozen-bubble