feat: migrate legacy playout workflow and scenes

scripts/Test-LegacyCutCoverage.ps1

@@ -0,0 +1,60 @@
+#Requires -Version 5.1
+
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory = $true)]
+    [string] $CutRoot
+)
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = 'Stop'
+
+if (-not [IO.Path]::IsPathRooted($CutRoot)) {
+    throw 'CutRoot must be an absolute path.'
+}
+
+$root = [IO.Path]::GetFullPath($CutRoot)
+if (-not (Test-Path -LiteralPath $root -PathType Container)) {
+    throw 'CutRoot does not identify an existing directory.'
+}
+
+# Active MainForm aliases for the 34 reachable builders. s8086 intentionally has no alias.
+$aliases = @(
+    '5001', 'N5001', '5006', '5011', '5016', '50160',
+    '5023', '5024', '5025', '5026', '5029',
+    '8018', '8032', '5032', '5037',
+    '5074', '5076', '5077', '5078', '5079',
+    '5080', '5081', '5082', '5083', '5084', '5085',
+    '5086', '50860', '5087', '5088',
+    '6001', '6067', '8001', '8002', '8003',
+    '8035', '8061', '8040', '8046', '8051', '8056',
+    '8067', '5068', '5070', '5072'
+)
+
+$missing = [Collections.Generic.List[string]]::new()
+$unsafe = [Collections.Generic.List[string]]::new()
+foreach ($alias in $aliases) {
+    $path = Join-Path $root ($alias + '.t2s')
+    if (-not (Test-Path -LiteralPath $path -PathType Leaf)) {
+        $missing.Add($alias)
+        continue
+    }
+
+    $item = Get-Item -LiteralPath $path -Force
+    if (($item.Attributes -band [IO.FileAttributes]::ReparsePoint) -ne 0 -or
+        $item.Length -le 0) {
+        $unsafe.Add($alias)
+    }
+}
+
+if ($missing.Count -ne 0 -or $unsafe.Count -ne 0) {
+    throw "Legacy cut coverage failed. Missing=$($missing.Count), Unsafe=$($unsafe.Count)."
+}
+
+[pscustomobject][ordered]@{
+    Status = 'Passed'
+    ReachableBuilders = 34
+    ActiveAliases = $aliases.Count
+    Missing = $missing.Count
+    Unsafe = $unsafe.Count
+}