fix(setup): defeat WaaSMedicSvc wuauserv healing + AutoAdminLogon Final gate

Two persistent Validate-SetupState failures despite §7.4 fixes:

1. wuauserv — Setup's Assert-Steps pass at exit but WaaSMedicSvc (tamper-protected,
   cannot be disabled) polls SCM ~30-60s and resets StartType to Manual.
   Fix: write Start=4 directly to registry key (SCM API alone is overrideable);
   deny WaaSMedicSvc write access to wuauserv registry key via ACL (best-effort,
   non-fatal if WinRM session lacks permission); re-enforce Start=4 after DISM
   in Cleanup; add Pre-Final re-affirmation block before Final gate.

2. AutoAdminLogon — Step 5c re-affirms it mid-script, but Steps 7-10 take hours
   and no Final gate check catches a late reset. Fix: add Pre-Final re-affirmation
   block (same as wuauserv) + add Assert-Step 'Final' 'AutoAdminLogon=1' to Final gate.

Also update WinISO default path to April 2026 refresh ISO.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

template/Setup-WinBuild2025.ps1

@@ -573,6 +573,12 @@ Write-Step "Disabling Windows Update permanently (post-update snapshot lockdown)
 # Stop + disable main WU service
 Stop-Service -Name wuauserv -Force -ErrorAction SilentlyContinue
 Set-Service  -Name wuauserv -StartupType Disabled
+# Write Start=4 directly to the service registry key in addition to the SCM call.
+# Set-Service calls ChangeServiceConfig (SCM API) which WaaSMedicSvc can override via its
+# own SCM call. The registry Start value requires WaaSMedicSvc to have registry write
+# access — denied by the ACL block below.
+Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\wuauserv' `
+    -Name Start -Value 4 -Type DWord -Force
 
 # Stop + disable Update Orchestrator Service (UsoSvc) — WU client in Server 2025
 Stop-Service -Name UsoSvc -Force -ErrorAction SilentlyContinue
@@ -603,6 +609,30 @@ foreach ($taskName in @('Scheduled Start', 'WakeTimer', 'Automatic App Update',
 }
 Write-Host "Windows Update scheduled tasks disabled (best-effort)."
 
+# Deny WaaSMedicSvc write access to the wuauserv service registry key so it cannot
+# reset Start back to Manual (2) or Automatic (3) after we set it to Disabled (4).
+# WaaSMedicSvc is a protected service that cannot itself be disabled; ACL denial
+# is the only reliable way to prevent it from healing the service startup type.
+# Best-effort: wrapped in try/catch so that a WinRM session permission failure is
+# non-fatal (the GPO keys + Start=4 still provide a good baseline).
+try {
+    $svcRegPath = 'HKLM:\SYSTEM\CurrentControlSet\Services\wuauserv'
+    $acl        = Get-Acl $svcRegPath
+    $medicSid   = [System.Security.Principal.NTAccount]'NT SERVICE\WaaSMedicSvc'
+    $denyRule   = New-Object System.Security.AccessControl.RegistryAccessRule(
+        $medicSid,
+        [System.Security.AccessControl.RegistryRights]'SetValue,CreateSubKey,WriteKey',
+        [System.Security.AccessControl.InheritanceFlags]::None,
+        [System.Security.AccessControl.PropagationFlags]::None,
+        [System.Security.AccessControl.AccessControlType]::Deny
+    )
+    $acl.AddAccessRule($denyRule)
+    Set-Acl $svcRegPath $acl
+    Write-Host "wuauserv: WaaSMedicSvc write-deny ACL applied."
+} catch {
+    Write-Warning "wuauserv ACL deny skipped (non-fatal — GPO keys + Start=4 still in place): $_"
+}
+
 # Validation
 Assert-Step 'WUDisable' 'wuauserv StartType Disabled' {
     (Get-Service wuauserv -ErrorAction Stop).StartType -eq 'Disabled'
@@ -991,6 +1021,8 @@ Write-Host "Disk cleanup complete."
 foreach ($svc in 'wuauserv', 'UsoSvc') {
     Set-Service -Name $svc -StartupType Disabled -ErrorAction SilentlyContinue
 }
+Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\wuauserv' `
+    -Name Start -Value 4 -Type DWord -Force -ErrorAction SilentlyContinue
 
 # Validation — leftover artifacts from this run should be gone
 # Note: do NOT assert SoftwareDistribution\Download empty.
@@ -1007,6 +1039,27 @@ Assert-Step 'Cleanup' 'wuauserv StartType Disabled after cache clear' {
 }
 } # end if (-not $SkipCleanup)
 
+# ── Pre-Final re-affirmation ──────────────────────────────────────────────────
+# Steps 7-10 (installs, cleanup, DISM) can take hours. During that window background
+# tasks or WaaSMedicSvc may reset AutoAdminLogon or wuauserv. Re-affirm both here
+# immediately before the Final gate so the snapshot captures clean state.
+
+$wlKey = 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon'
+$wlNow = Get-ItemProperty -Path $wlKey -ErrorAction SilentlyContinue
+if ($wlNow.AutoAdminLogon -ne '1' -or $wlNow.DefaultUserName -ne 'Administrator') {
+    Set-ItemProperty -Path $wlKey -Name AutoAdminLogon    -Value '1'             -Type String -Force
+    Set-ItemProperty -Path $wlKey -Name DefaultUserName   -Value 'Administrator' -Type String -Force
+    Set-ItemProperty -Path $wlKey -Name DefaultDomainName -Value '.'             -Type String -Force
+}
+if ($AdminPassword -ne '') {
+    Set-ItemProperty -Path $wlKey -Name DefaultPassword -Value $AdminPassword -Type String -Force
+}
+
+Stop-Service -Name wuauserv -Force -ErrorAction SilentlyContinue
+Set-Service  -Name wuauserv -StartupType Disabled
+Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\wuauserv' `
+    -Name Start -Value 4 -Type DWord -Force
+
 # ── Final pre-snapshot validation ────────────────────────────────────────────
 Write-Step "Final pre-snapshot validation"
 
@@ -1028,6 +1081,10 @@ Assert-Step 'Final' 'dotnet, python, msbuild all resolvable' {
     (Test-Path 'C:\Python\python.exe' -PathType Leaf) -and
     (Test-Path $msbuildPath -PathType Leaf)
 }
+Assert-Step 'Final' 'AutoAdminLogon=1, DefaultUserName=Administrator' {
+    $wl = Get-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon' -ErrorAction Stop
+    $wl.AutoAdminLogon -eq '1' -and $wl.DefaultUserName -eq 'Administrator'
+}
 Assert-Step 'Final' 'Windows Update permanently disabled' {
     (Get-Service wuauserv -ErrorAction Stop).StartType -eq 'Disabled'
 }