feat(benchmark): add static IP support to Measure-CIBenchmark

- Add -StaticIP/-Netmask/-Gateway params; injects guestinfo into cloned
  VMX before start, mirroring job.py _inject_guestinfo_ip behaviour
- Add -GuestInfoOnly switch to Get-GuestIPAddress: skips vmrun
  getGuestIPAddress fallback to prevent race where transient DHCP address
  is returned before ci-static-ip.ps1 finishes reconfiguring the NIC
- Benchmark passes -GuestInfoOnly automatically when -StaticIP is set
- staticIP field added to benchmark.jsonl for DHCP vs static comparison

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

scripts/Measure-CIBenchmark.ps1

@@ -89,7 +89,14 @@ param(
                                '/var/lib/ci/logs/'
                            } else {
                                'F:\CI\Logs'
-                           })
+                           }),
+
+    # Optional static IP injection (mirrors ip_pool in job.py).
+    # If supplied, guestinfo.ip-assignment/netmask/gateway are written into the
+    # cloned VMX before start so ci-static-ip.ps1 applies the IP at boot.
+    [string] $StaticIP  = '',
+    [string] $Netmask   = '255.255.255.0',
+    [string] $Gateway   = ''
 )
 
 Set-StrictMode -Version Latest
@@ -138,9 +145,27 @@ if (-not (Test-Path $OutputDir)) {
     New-Item -ItemType Directory -Path $OutputDir -Force | Out-Null
 }
 
+function Set-GuestInfoIP {
+    param([string]$VmxPath, [string]$IP, [string]$Mask, [string]$Gw)
+    $keys   = @('guestinfo.ip-assignment', 'guestinfo.netmask', 'guestinfo.gateway')
+    $lines  = (Get-Content -LiteralPath $VmxPath -Encoding UTF8) |
+                  Where-Object { ($_ -split '=')[0].Trim().ToLower() -notin $keys }
+    $lines += "guestinfo.ip-assignment = `"$IP`""
+    if ($Mask) { $lines += "guestinfo.netmask = `"$Mask`"" }
+    if ($Gw)   { $lines += "guestinfo.gateway = `"$Gw`"" }
+    Set-Content -LiteralPath $VmxPath -Value $lines -Encoding UTF8
+}
+
 $benchmarkLog = Join-Path $OutputDir 'benchmark.jsonl'
 $results      = [System.Collections.Generic.List[pscustomobject]]::new()
 
+$useStaticIP = $StaticIP -match '^\d{1,3}(\.\d{1,3}){3}$'
+if ($useStaticIP) {
+    Write-Host "[bench] Static IP mode: $StaticIP / $Netmask  gw=$Gateway"
+} else {
+    Write-Host "[bench] DHCP mode (no -StaticIP supplied)"
+}
+
 Write-Host ""
 Write-Host "=== CI Benchmark  template: $(Split-Path $TemplatePath -Leaf)  snapshot: $SnapshotName  iterations: $Iterations ==="
 Write-Host ""
@@ -186,6 +211,12 @@ for ($i = 1; $i -le $Iterations; $i++) {
             Write-Warning "[bench] Could not measure clone size: $_"
         }
 
+        # ── Static IP injection (before start) ───────────────────────────────
+        if ($useStaticIP) {
+            Set-GuestInfoIP -VmxPath $cloneVmx -IP $StaticIP -Mask $Netmask -Gw $Gateway
+            Write-Host "[bench] guestinfo injected: $StaticIP"
+        }
+
         # ── Phase: start ──────────────────────────────────────────────────────
         Write-Host "[bench] Starting VM..."
         $sw.Restart()
@@ -198,7 +229,7 @@ for ($i = 1; $i -le $Iterations; $i++) {
         Write-Host "[bench] Waiting for guest IP..."
         $sw.Restart()
         $vmIP = Get-GuestIPAddress -VmrunPath $VmrunPath -VmxPath $cloneVmx `
-                    -TimeoutSeconds $TimeoutSeconds
+                    -TimeoutSeconds $TimeoutSeconds -GuestInfoOnly:$useStaticIP
         if (-not $vmIP) { throw "Timed out waiting for guest IP after $TimeoutSeconds s" }
         $t.ip   = [math]::Round($sw.Elapsed.TotalSeconds, 2)
         $t.vmIP = $vmIP
@@ -250,6 +281,7 @@ for ($i = 1; $i -le $Iterations; $i++) {
         template     = Split-Path $TemplatePath -Leaf
         snapshot     = $SnapshotName
         guestOS      = $resolvedGuestOS
+        staticIP     = if ($useStaticIP) { $StaticIP } else { $null }
         cloneSec     = $t.clone
         startSec     = $t.start
         ipSec        = $t.ip