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/_Common.psm1

@@ -254,10 +254,16 @@ function Get-GuestIPAddress {
     param(
         [Parameter(Mandatory)] [string] $VmrunPath,
         [Parameter(Mandatory)] [string] $VmxPath,
-        [int]                           $TimeoutSeconds = 120
+        [int]                           $TimeoutSeconds = 120,
+        # When set, skip vmrun getGuestIPAddress fallback and poll only
+        # guestinfo.ci-ip. Use when guestinfo.ip-assignment was injected into
+        # the VMX — avoids returning a transient DHCP address before
+        # ci-static-ip.ps1 has finished reconfiguring the NIC.
+        [switch]                        $GuestInfoOnly
     )
 
-    Write-Host "[Get-GuestIPAddress] Polling for VM IP (max ${TimeoutSeconds}s)..."
+    $modeLabel = if ($GuestInfoOnly) { 'guestinfo only' } else { 'guestinfo + getGuestIPAddress' }
+    Write-Host "[Get-GuestIPAddress] Polling for VM IP (max ${TimeoutSeconds}s, mode: $modeLabel)..."
     $deadline = (Get-Date).AddSeconds($TimeoutSeconds)
     $attempt  = 0
 
@@ -279,15 +285,18 @@ function Get-GuestIPAddress {
             return $ipOut
         }
 
-        # Fallback: vmrun getGuestIPAddress (VMware Tools / open-vm-tools required).
-        $savedEap = $ErrorActionPreference; $ErrorActionPreference = 'Continue'
-        $ipOut2 = (& $VmrunPath -T ws getGuestIPAddress $VmxPath 2>&1).Trim()
-        $ipRc2  = $LASTEXITCODE
-        $ErrorActionPreference = $savedEap
+        # Fallback: vmrun getGuestIPAddress — skipped when GuestInfoOnly is set
+        # to avoid returning a transient DHCP address during static-IP reconfiguration.
+        if (-not $GuestInfoOnly) {
+            $savedEap = $ErrorActionPreference; $ErrorActionPreference = 'Continue'
+            $ipOut2 = (& $VmrunPath -T ws getGuestIPAddress $VmxPath 2>&1).Trim()
+            $ipRc2  = $LASTEXITCODE
+            $ErrorActionPreference = $savedEap
 
-        if ($ipRc2 -eq 0 -and $ipOut2 -match '^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$') {
-            Write-Host "[Get-GuestIPAddress] IP via getGuestIPAddress: $ipOut2"
-            return $ipOut2
+            if ($ipRc2 -eq 0 -and $ipOut2 -match '^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$') {
+                Write-Host "[Get-GuestIPAddress] IP via getGuestIPAddress: $ipOut2"
+                return $ipOut2
+            }
         }
 
         Start-Sleep -Seconds 2