Use [Environment]::MachineName instead of $env:COMPUTERNAME

Live kernel NetBIOS name instead of the PowerShell process-env cache.

$env:COMPUTERNAME is populated when PowerShell starts and does not
update if the PC gets renamed (common on Intune-managed Autopilot /
AADJ devices that come up with a DESKTOP-XXXXXXXX name and get
renamed by policy post-imaging). Until the next reboot, the env var
stays stale while 'hostname.exe' already reports the new name.

That mismatch showed up live on the first production retrofit: the
status.json was written under _outputs/logs/DESKTOP-XXXXXXXX/
instead of under the device's current name, and the
TargetHostnames filter and monitor drift-check would likewise see
the stale name.

[Environment]::MachineName reads from the kernel on each call, so
it always returns the current NetBIOS name. Swapped at all five
callsites in GE-Enforce.ps1, Register-GEEnforce.ps1, and
Install-FromManifest.ps1.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

playbook/shopfloor-setup/common/lib/Install-FromManifest.ps1

@@ -375,7 +375,11 @@ function Test-PCTypeMatches {
 function Test-HostnameMatches {
     param($App)
     if (-not $App.TargetHostnames -or $App.TargetHostnames.Count -eq 0) { return $true }
-    $myName = $env:COMPUTERNAME
+    # [System.Environment]::MachineName reads the live NetBIOS name from the
+    # kernel. $env:COMPUTERNAME is cached in the process environment at PS
+    # startup and is stale after a PC rename until the next reboot - which
+    # matters on Intune-managed PCs that get renamed post-imaging.
+    $myName = [System.Environment]::MachineName
     foreach ($h in $App.TargetHostnames) {
         if ($h -ieq $myName)   { return $true }
         if ($myName -ilike $h) { return $true }  # glob patterns: WJS-*, *-SHOP-*
@@ -405,7 +409,7 @@ foreach ($app in $config.Applications) {
     }
 
     if (-not (Test-HostnameMatches -App $app)) {
-        Write-InstallLog "  TargetHostnames filter: entry targets $($app.TargetHostnames -join ',') but PC is $env:COMPUTERNAME - skipping"
+        Write-InstallLog "  TargetHostnames filter: entry targets $($app.TargetHostnames -join ',') but PC is $([System.Environment]::MachineName) - skipping"
         $pcFiltered++
         continue
     }