test(bench): typeperf CPU/GPU/NPU counter capture script

scripts/bench/capture-counters.ps1

@@ -0,0 +1,24 @@
+# Best-effort system-counter capture alongside a bench run: total CPU utility
+# + GPU compute-engine utilization (and NPU engines where the OS exposes them;
+# absent counters are skipped by typeperf). Primary CPU metric remains the
+# harness's in-process CPU-seconds — this is corroborating evidence.
+param(
+    [string]$Out = "bench-results\counters.csv",
+    [int]$Seconds = 120
+)
+$ErrorActionPreference = "Stop"
+New-Item -ItemType Directory -Force (Split-Path -Parent $Out) | Out-Null
+$counters = @(
+    "\Processor Information(_Total)\% Processor Utility",
+    "\GPU Engine(*engtype_Compute)\Utilization Percentage",
+    "\NPU Engine(*)\Utilization Percentage"
+)
+# typeperf exits nonzero if ANY counter is invalid; probe each and keep the valid ones.
+$valid = @()
+foreach ($c in $counters) {
+    typeperf $c -sc 1 | Out-Null
+    if ($LASTEXITCODE -eq 0) { $valid += $c }
+}
+if ($valid.Count -eq 0) { throw "no usable counters on this machine" }
+typeperf $valid -si 1 -sc $Seconds -f CSV -o $Out -y | Out-Null
+Write-Output "captured $($valid.Count) counter set(s) for ${Seconds}s -> $Out"