Fix boot-critical, session, and UX bugs found in round-3 UX audit

Snapshots panel was non-functional (wrong snapper flag); breadgreet picked
the wrong session .desktop and skipped bos-session's PATH fixup; Calamares
aborted offline installs over an unnecessary packages module; snapshot
rollback silently no-op'd on BOS's pinned-subvolume layout (now points at
grub-btrfs instead); breadcrumbs was configurable but had no daemon to run
it. Also: SUPER+I double-bind, breadpaper/packages panels blocking the GTK
main thread, dead polkit rule, and a sweep of smaller drift (default
sidebar view, stale wording, missing .desktop launchers, wallpaper daemon
not recording its own default).

iso/airootfs/etc/skel/.config/hypr/hypridle.conf

@@ -3,7 +3,7 @@
 # playback, etc. won't dim or suspend the machine). Vendor-neutral: nothing here
 # is Intel/AMD specific.
 general {
-    lock_cmd         = pidof hyprlock || hyprlock
+    lock_cmd         = pidof breadlock || breadlock
     before_sleep_cmd = loginctl lock-session
     after_sleep_cmd  = hyprctl dispatch dpms on
     ignore_dbus_inhibit = false