fix(collector): surface PCIe link-speed degradation in component-status DB, sample it under load

pcie:gpu:<vendor> in the component-status DB (what the Hardware
Summary/webui "check passed" status reads) was only ever written by SAT
diag results, and none of the nvidia/nvidia-config/nvidia-interconnect/
nvidia-bandwidth SAT jobs check PCIe link speed. So a real Gen1/Gen4
degradation the collector already flagged as Warning in the hardware
snapshot never reached the DB-backed status, and the audit kept
reporting "OK" despite GPUs training at Gen1 with BMC showing x16.

Add writePCIeGPUStatusesToDB, mirroring the existing PSU write-through,
so RunAudit pushes the collector's PCIe status into the DB alongside
SAT results.

Also add export/gpu/pcie-nvidia-link-under-load.txt to the support
bundle: NVIDIA drivers deliberately downclock PCIe at idle to save
power and re-train to full speed under load, so an idle Gen1 reading
alone can't distinguish real hardware/riser degradation from normal
power management. Resample the same sysfs link attributes while
bee-gpu-burn is actively loading the GPUs so both bundles ship
together.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

audit/internal/app/support_bundle.go

@@ -308,6 +308,38 @@ for d in /sys/bus/pci/devices/*/; do
     printf "  %-22s %s\n" "$f" "$(cat "$d/$f" 2>/dev/null)"
   done
 done
+`}},
+	// A Gen1-vs-Gen4 link speed reading at idle is ambiguous: NVIDIA drivers
+	// deliberately downclock PCIe in low power states and re-train to full
+	// speed under load, so pcie-nvidia-link.txt alone can't tell a real
+	// hardware/riser fault from normal power management. Re-sample the same
+	// sysfs attributes while bee-gpu-burn is actively loading the GPUs — if
+	// the link comes up here, the idle Gen1 reading above was power saving,
+	// not a fault.
+	{name: "export/gpu/pcie-nvidia-link-under-load.txt", cmd: []string{"sh", "-c", `
+if ! command -v bee-gpu-burn >/dev/null 2>&1; then
+  echo "bee-gpu-burn not found; cannot sample PCIe link speed under load"
+  exit 0
+fi
+bee-gpu-burn --seconds 8 --size-mb 64 >/tmp/bee-pcie-load-burn.log 2>&1 &
+burn_pid=$!
+sleep 3
+for d in /sys/bus/pci/devices/*/; do
+  vendor=$(cat "$d/vendor" 2>/dev/null)
+  [ "$vendor" = "0x10de" ] || continue
+  class=$(cat "$d/class" 2>/dev/null)
+  case "$class" in
+    0x030000|0x030200) ;;
+    *) continue ;;
+  esac
+  dev=$(basename "$d")
+  echo "=== $dev ==="
+  for f in current_link_speed current_link_width max_link_speed max_link_width; do
+    printf "  %-22s %s\n" "$f" "$(cat "$d/$f" 2>/dev/null)"
+  done
+done
+wait "$burn_pid" 2>/dev/null || true
+rm -f /tmp/bee-pcie-load-burn.log
 `}},
 	{name: "export/gpu/pcie-aer-sysfs.txt", cmd: []string{"sh", "-c", `
 found=0