feat(firmware): install probe tools in live image + surface nic/hba gaps

mkosi.conf: add ipmitool, ethtool, nvme-cli so the Firmware stage
can actually read BMC revisions, NIC firmware versions, and fall
back to nvme-cli when sysfs firmware_rev is missing.

firmware.go: probeNICFirmware and probeHBAFirmware now return
(snapshots, warning) so a missing ethtool/lspci surfaces in the
stage log the same way probeBIOS/probeBMC already do. Before, a
host without ethtool silently reported "bios=1 nvme_fw=1
microcode=1" with no hint that nic coverage was dropped.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

live-image/mkosi.conf

@@ -57,6 +57,12 @@ Packages=
     lm-sensors
     e2fsprogs
     util-linux
+    # Firmware probe tooling. Without these, the Firmware stage silently
+    # skips whole components (ethtool → nic, nvme-cli → nvme fallback) or
+    # emits a cosmetic "not installed" warning (ipmitool → bmc).
+    ipmitool
+    ethtool
+    nvme-cli
     # Firmware. firmware-linux-nonfree on bookworm is a thin metapackage
     # that does NOT pull i915 GuC/HuC — those live in firmware-misc-nonfree.
     # Enumerate explicitly so the blob for whatever hardware we boot on