feat(isobuild): add multi-architecture build and Raspberry Pi support in installer and build tooling

isobuild/config/live-build/package-lists/base.list.chroot

@@ -1,4 +1,7 @@
 # EcoOS Base Packages
+# Common packages for all architectures
+# Architecture-specific packages are in base-{amd64,arm64,rpi}.list.chroot
+
 # System essentials
 linux-image-generic
 linux-headers-generic
@@ -8,10 +11,8 @@ network-manager
 openssh-server
 sudo
 
-# EFI bootloader (required for UEFI boot)
-grub-efi-amd64
-grub-efi-amd64-signed
-shim-signed
+# Note: EFI bootloader packages are architecture-specific
+# See base-amd64.list.chroot, base-arm64.list.chroot, base-rpi.list.chroot
 
 # Sway + Wayland
 sway