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/builder/smoketest.sh

@@ -52,6 +52,14 @@ else
     fail "nvidia-smi: NOT FOUND"
 fi
 
+for tool in bee-gpu-burn bee-john-gpu-stress bee-nccl-gpu-stress all_reduce_perf; do
+    if p=$(PATH="/usr/local/bin:$PATH" command -v "$tool" 2>/dev/null); then
+        ok "$tool found: $p"
+    else
+        fail "$tool: NOT FOUND"
+    fi
+done
+
 echo ""
 echo "-- NVIDIA modules --"
 KO_DIR="/usr/local/lib/nvidia"