Add HPC tuning: PCIe ASPM off, C-states, performance CPU governor

- grub.cfg + isolinux/live.cfg.in: add pcie_aspm=off,
  intel_idle.max_cstate=1 and processor.max_cstate=1 to all
  non-failsafe boot entries
- bee-hpc-tuning: new script that sets all CPU cores to performance
  governor via sysfs and logs THP state at boot
- bee-hpc-tuning.service: runs before bee-nvidia and bee-audit
- 9000-bee-setup.hook.chroot: enable service and mark script executable

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

iso/overlay/usr/local/bin/bee-hpc-tuning

@@ -0,0 +1,41 @@
+#!/bin/sh
+# bee-hpc-tuning — apply HPC tuning for deterministic benchmarking
+# Called by bee-hpc-tuning.service at boot.
+
+log() { echo "[bee-hpc-tuning] $*"; }
+
+# ── CPU governor ────────────────────────────────────────────────────────────
+# Set all CPU cores to performance governor via sysfs.
+# cpupower is not available; write directly to scaling_governor.
+governor_ok=0
+governor_fail=0
+for gov_path in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do
+    [ -f "$gov_path" ] || continue
+    if echo performance > "$gov_path" 2>/dev/null; then
+        governor_ok=$((governor_ok + 1))
+    else
+        governor_fail=$((governor_fail + 1))
+    fi
+done
+
+if [ "$governor_ok" -gt 0 ] && [ "$governor_fail" -eq 0 ]; then
+    log "CPU governor set to performance on ${governor_ok} core(s)"
+elif [ "$governor_ok" -gt 0 ]; then
+    log "WARN: CPU governor: ${governor_ok} OK, ${governor_fail} failed"
+elif [ "$governor_fail" -gt 0 ]; then
+    log "WARN: failed to set CPU governor on ${governor_fail} core(s)"
+else
+    log "WARN: no cpufreq scaling_governor paths found (C-state governor or HW-controlled)"
+fi
+
+# ── Transparent Huge Pages ───────────────────────────────────────────────────
+# Kernel cmdline sets transparent_hugepage=always at boot, but confirm and log.
+thp_path=/sys/kernel/mm/transparent_hugepage/enabled
+if [ -f "$thp_path" ]; then
+    current=$(cat "$thp_path" 2>/dev/null)
+    log "transparent_hugepage: ${current}"
+else
+    log "WARN: transparent_hugepage sysfs path not found"
+fi
+
+log "done"