fix(partitioning): create separate /boot for LVM-based filesystems

VMware EFI firmware may not initialize all SCSI devices before GRUB
runs, preventing LVM assembly when the root LV spans multiple disks.
A separate /boot partition (the standard RHEL Anaconda layout) lets
GRUB load kernels without LVM; the kernel initramfs handles LVM
activation with proper device waiting.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

roles/partitioning/defaults/main.yml

@@ -9,7 +9,10 @@ partitioning_boot_size_mib: 1024
 partitioning_use_full_disk: true
 partitioning_separate_boot: >-
   {{
-    (system_cfg.luks.enabled | bool)
+    (
+      (system_cfg.luks.enabled | bool)
+      or (system_cfg.filesystem != 'btrfs')
+    )
     and (os not in ['archlinux'])
   }}
 partitioning_boot_fs_fstype: >-