fix: pcie gen, nccl binary, netconf sudo, boot noise, firmware cleanup

- nvidia collector: read pcie.link.gen.current/max from nvidia-smi instead
  of sysfs to avoid false Gen1 readings when GPU is in ASPM idle state
- build: remove bee-nccl-gpu-stress from rm -f list so shell script from
  overlay is not silently dropped from the ISO
- smoketest: add explicit checks for bee-gpu-burn, bee-john-gpu-stress,
  bee-nccl-gpu-stress, all_reduce_perf
- netconf: re-exec via sudo when not root to fix RTNETLINK/resolv.conf errors
- auto/config: reduce loglevel 7→3 to show clean systemd output on boot
- auto/config: blacklist snd_hda_intel and related audio modules (unused on servers)
- package-lists: remove firmware-intel-sound and firmware-amd-graphics from
  base list; move firmware-amd-graphics to bee-amd variant only
- bible-local: mark memtest ADR resolved, document working solution

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

iso/overlay/usr/local/bin/netconf

@@ -3,6 +3,11 @@
 # Type 'a' at any prompt to abort, 'b' to go back.
 set -e
 
+# Requires root for ip/dhclient/resolv.conf — re-exec via sudo if needed.
+if [ "$(id -u)" -ne 0 ]; then
+    exec sudo "$0" "$@"
+fi
+
 abort() { echo "Aborted."; exit 0; }
 
 ask() {