feat: harden isolated Tornado test workflow

scripts/Test-WebPlayout.ps1

@@ -0,0 +1,68 @@
+#Requires -Version 5.1
+
+[CmdletBinding()]
+param(
+    [string] $NodePath
+)
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = 'Stop'
+
+function Resolve-NodePath {
+    param([AllowEmptyString()][string] $ExplicitPath)
+
+    if (-not [string]::IsNullOrWhiteSpace($ExplicitPath)) {
+        if (-not [IO.Path]::IsPathRooted($ExplicitPath) -or
+            -not (Test-Path -LiteralPath $ExplicitPath -PathType Leaf)) {
+            throw 'NodePath must identify an existing absolute node executable path.'
+        }
+
+        return [IO.Path]::GetFullPath($ExplicitPath)
+    }
+
+    $command = Get-Command node -CommandType Application -ErrorAction SilentlyContinue |
+        Select-Object -First 1
+    if ($null -ne $command) {
+        return $command.Source
+    }
+
+    $programFiles = [Environment]::GetFolderPath(
+        [Environment+SpecialFolder]::ProgramFiles)
+    $candidates = @(
+        (Join-Path $programFiles 'Microsoft Visual Studio\18\Community\MSBuild\Microsoft\VisualStudio\NodeJs\node.exe'),
+        (Join-Path $programFiles 'Microsoft Visual Studio\2022\Community\MSBuild\Microsoft\VisualStudio\NodeJs\node.exe')
+    )
+    foreach ($candidate in $candidates) {
+        if (Test-Path -LiteralPath $candidate -PathType Leaf) {
+            return [IO.Path]::GetFullPath($candidate)
+        }
+    }
+
+    throw 'A Node.js executable was not found. Pass its absolute path with -NodePath.'
+}
+
+$node = Resolve-NodePath -ExplicitPath $NodePath
+$repositoryRoot = [IO.Path]::GetFullPath((Join-Path $PSScriptRoot '..'))
+$scripts = @(
+    (Join-Path $repositoryRoot 'Web\playout-safety.js'),
+    (Join-Path $repositoryRoot 'Web\app.js')
+)
+$test = Join-Path $repositoryRoot 'tests\Web\playout-safety.test.cjs'
+
+foreach ($script in $scripts) {
+    & $node --check $script
+    if ($LASTEXITCODE -ne 0) {
+        throw "JavaScript syntax validation failed with exit code $LASTEXITCODE."
+    }
+}
+
+& $node --test $test
+if ($LASTEXITCODE -ne 0) {
+    throw "Web playout tests failed with exit code $LASTEXITCODE."
+}
+
+[pscustomobject][ordered]@{
+    Status = 'Passed'
+    SyntaxFiles = $scripts.Count
+    TestFile = [IO.Path]::GetFileName($test)
+}