v0.54.0: format-safety foundation — unclaimed-disk guard + guarded-mkfs wrapper

Impl-1. Format now runs a mandatory unclaimed-disk guard (internal/storage/claim.go:
SystemDisks + lsblk member-FSTYPE + foreign-mount + RO + pvs/zpool; fail-safe →
CLAIMED) before any mkfs — refuses the OS disk / LVM PV / ZFS-mdraid member /
foreign-mounted device even when non-data-bearing (guard sits in Format, not the
handler). Below the agent, mkfs goes ONLY through configs/felhom-mkfs-guarded.sh
(sudoers no longer allowlists raw mkfs.*), which re-checks the catastrophic cases
as root. Read-only pvs/zpool added to FELHOM_DISK. Tests + red-proof; capability
manifest updated. go build/vet/test clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

cmd/felhom-agent/main.go

@@ -45,7 +45,7 @@ import (
 
 // version is the agent version. Overridable at build time with
 // -ldflags "-X main.version=<v>"; defaults to the in-repo CHANGELOG version.
-var version = "0.53.0"
+var version = "0.54.0"
 
 // runGuestHook is the PVE pre-start hook body (`felhom-agent guest-hook <vmid> <phase>`). On the
 // pre-start phase it creates placeholder dirs for any absent bind-mount source so the guest always boots