Review changes batch 6 of 6

tests/capture-g11-g12-states-contract.ps1

@@ -0,0 +1,14 @@
+$ErrorActionPreference = 'Stop'
+$root = Split-Path -Parent $PSScriptRoot
+$capture = Get-Content -LiteralPath (Join-Path $root 'scripts/capture-chrome-page.js') -Raw -Encoding utf8
+
+foreach ($required in @(
+  'prepareG11State', 'g11-validation', 'g11-saved',
+  'prepareG12State', 'g12-validation', 'g12-save-error', 'g12-saved'
+)) {
+  if ($capture -notmatch [regex]::Escape($required)) { throw "G11/G12 capture state missing: $required" }
+}
+if ($capture -notmatch 'await prepareG11State\(send, action\)') { throw 'Capture runner does not prepare G11 states' }
+if ($capture -notmatch 'await prepareG12State\(send, action\)') { throw 'Capture runner does not prepare G12 states' }
+
+Write-Output 'CAPTURE-G11-G12-STATES-CONTRACT PASS'