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/usr/local/bin/bos-live-setup

@@ -18,16 +18,18 @@ if ! id liveuser &>/dev/null; then
     passwd -d liveuser >/dev/null
 fi
 
-# Layer the installer onto the live desktop: auto-launch it, and bind Super+I to
-# relaunch it after it's been closed. Appended (in Lua) to the skel hyprland.lua
-# native config so the full desktop stays intact.
+# Layer the installer onto the live desktop: auto-launch it, and bind
+# Super+Shift+I to relaunch it after it's been closed. Appended (in Lua) to
+# the skel hyprland.lua native config so the full desktop stays intact.
+# NOTE: plain SUPER+I is float-toggle in the skel config — don't reuse it
+# here, it was tried once and silently double-bound both actions.
 HYPR=/home/liveuser/.config/hypr/hyprland.lua
 install -d -m 0755 -o liveuser -g liveuser /home/liveuser/.config/hypr
 if ! grep -q bos-launch-calamares "$HYPR" 2>/dev/null; then
     cat >>"$HYPR" <<'EOF'
 
 -- --- live-media installer (added by bos-live-setup; absent on installed system) ---
-hl.bind("SUPER + I", hl.dsp.exec_cmd("bos-launch-calamares"))
+hl.bind("SUPER + SHIFT + I", hl.dsp.exec_cmd("bos-launch-calamares"))
 hl.on("hyprland.start", function() hl.dispatch(hl.dsp.exec_cmd("bos-launch-calamares")) end)
 EOF
 fi