feat(anaconda): improve installation process and post-install handling

- Add kernel copy step in %pre to ensure vmlinuz-linux is available for mkinitcpio
- Refactor xinitrc post-install log detection to use /tmp/fws-post-chroot.log copied by kickstart
- Add success detection based on mkinitcpio and grub-install log markers
- Display success screen and poweroff on successful installation, show debug logs on failure
- Add load_policy and setstatus stub scripts to suppress SELinux-related Anaconda warnings
- Force MBR partition table (--disklabel=msdos) for BIOS boot compatibility
- Create standard mkinitcpio preset to replace archiso-specific configuration
- Automatically inject lvm2 hook when root is on LVM
- Fix GRUB installation to properly extract disk path from lsblk output
- Downgrade version to 0.5.3 (development/testing release)

configs/releng/profiledef.sh

@@ -22,4 +22,6 @@ file_permissions=(
   ["/usr/local/bin/choose-mirror"]="0:0:755"
   ["/usr/local/bin/Installation_guide"]="0:0:755"
   ["/usr/local/bin/livecd-sound"]="0:0:755"
+  ["/usr/bin/load_policy"]="0:0:755"
+  ["/usr/bin/setstatus"]="0:0:755"
 )