Bake bread ecosystem into the ISO + full live desktop; fix installer timeout

- packages.x86_64: add bread, breadbar, breadbox, breadcrumbs, breadpad,
  bos-settings so they ship in the squashfs and reach the target via unpackfs
  (no network needed; install works fully offline)
- shellprocess.conf: set timeout 1800 — Calamares' 10s default was killing
  post-install.sh partway (the real cause of the empty /boot + ESP); the "-"
  prefix had been masking the kill as success
- bos-live-setup: live user now boots the real BOS desktop from /etc/skel
  (breadd + breadbar + breadbox) with the installer layered on top
  (auto-launch + Super+I), instead of an installer-only kiosk
- post-install.sh: drop the now-redundant networked `bakery install`

iso/airootfs/etc/calamares/modules/shellprocess.conf

@@ -1,3 +1,9 @@
 ---
+# Calamares defaults shellprocess to a 10-second timeout. post-install.sh runs
+# mkinitcpio, grub-install, grub-mkconfig, snapper setup and a networked bakery
+# install — minutes of work — so without a generous timeout it gets killed
+# partway (leaving /boot and the ESP half-populated → unbootable system). The
+# leading "-" keeps a non-zero exit non-fatal to the install.
+timeout: 1800
 script:
   - "-/usr/bin/bash /etc/calamares/post-install.sh"