Tighten cutter phase span validation

setup_venv.ps1

@@ -7,6 +7,34 @@
 $ErrorActionPreference = "Stop"
 $VENV_DIR = ".venv"
 
+function Invoke-CapturedProcess {
+    param(
+        [Parameter(Mandatory = $true)][string]$FilePath,
+        [Parameter(Mandatory = $false)][string[]]$Arguments = @()
+    )
+
+    $psi = [System.Diagnostics.ProcessStartInfo]::new()
+    $psi.FileName = $FilePath
+    foreach ($arg in $Arguments) {
+        [void]$psi.ArgumentList.Add($arg)
+    }
+    $psi.UseShellExecute = $false
+    $psi.RedirectStandardOutput = $true
+    $psi.RedirectStandardError = $true
+    $psi.CreateNoWindow = $true
+
+    $process = [System.Diagnostics.Process]::Start($psi)
+    $stdout = $process.StandardOutput.ReadToEnd()
+    $stderr = $process.StandardError.ReadToEnd()
+    $process.WaitForExit()
+
+    $combined = (($stdout + "`n" + $stderr).Trim())
+    if ($process.ExitCode -ne 0) {
+        throw "Command failed ($($process.ExitCode)): $FilePath $($Arguments -join ' ')`n$combined"
+    }
+    return $combined
+}
+
 function Resolve-ProjectPython {
     $cmd = Get-Command python -ErrorAction SilentlyContinue
     if ($cmd) {
@@ -35,7 +63,7 @@ Write-Host ""
 
 # ---- 1. Check Python version ------------------------------------------------
 $PROJECT_PYTHON = Resolve-ProjectPython
-$pythonVersion = & $PROJECT_PYTHON --version 2>&1
+$pythonVersion = Invoke-CapturedProcess $PROJECT_PYTHON @("--version")
 Write-Host "Python: $pythonVersion"
 if ($pythonVersion -notmatch "3\.(1[1-9]|[2-9]\d)") {
     Write-Error "Python 3.11+ required. Found: $pythonVersion"
@@ -48,8 +76,8 @@ if (Test-Path $VENV_DIR) {
     $venvOk = $false
     if (Test-Path $existingVenvPython) {
         try {
-            $existingVersion = & $existingVenvPython --version 2>&1
-            $venvOk = $LASTEXITCODE -eq 0 -and $existingVersion -match "3\.(1[1-9]|[2-9]\d)"
+            $existingVersion = Invoke-CapturedProcess $existingVenvPython @("--version")
+            $venvOk = $existingVersion -match "3\.(1[1-9]|[2-9]\d)"
         } catch {
             $venvOk = $false
         }
@@ -60,12 +88,12 @@ if (Test-Path $VENV_DIR) {
     } else {
         Write-Host "Existing virtual environment is not usable. Recreating '$VENV_DIR' ..." -ForegroundColor Yellow
         Remove-Item -LiteralPath $VENV_DIR -Recurse -Force
-        & $PROJECT_PYTHON -m venv $VENV_DIR
+        Invoke-CapturedProcess $PROJECT_PYTHON @("-m", "venv", $VENV_DIR) | Out-Null
         Write-Host "Done." -ForegroundColor Green
     }
 } else {
     Write-Host "Creating virtual environment in '$VENV_DIR' ..." -ForegroundColor Green
-    & $PROJECT_PYTHON -m venv $VENV_DIR
+    Invoke-CapturedProcess $PROJECT_PYTHON @("-m", "venv", $VENV_DIR) | Out-Null
     Write-Host "Done." -ForegroundColor Green
 }