Shopfloor unattend: move Orders 4/5 logic to external PS1 scripts

FlatUnattendW10-shopfloor.xml was rejected by Windows OOBE with
"the answer file is invalid" after the earlier tower-no-WiFi fix.
Root cause: the inline PowerShell in <CommandLine> for Orders 4 and
5 exceeded the SynchronousCommand CommandLine length limit (~1024
chars) and/or contained characters the unattend schema validator
dislikes.

Fix: move the logic to two external PS1 scripts and shrink both
CommandLine entries to ~85 chars each that just invoke the scripts.

- playbook/wait-for-internet.ps1: 60s interactive prompt ("connect
  production network now"), then poll TCP 443 to login.microsoft-
  online.us for up to 10 min with a hard timeout so the loop always
  exits. Uses Test-NetConnection -Port 443 (not Test-Connection /
  ICMP) because Microsoft 365 edges do not reliably respond to ping.
- playbook/migrate-to-wifi.ps1: Gates the entire wired-disable
  migration on "does a WiFi adapter exist?" If not (tower), the
  script is a no-op. If yes, disable wired / wait for WiFi internet
  with a 5 min timeout / re-enable wired on timeout fallback.
- startnet.cmd stages both new scripts to W:\Enrollment\ next to
  run-enrollment.ps1 during the WinPE phase.
- FlatUnattendW10-shopfloor.xml Orders 4 and 5 shrunk to short
  invocations of C:\Enrollment\wait-for-internet.ps1 and
  C:\Enrollment\migrate-to-wifi.ps1.
- startnet-template.cmd kept in sync.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

playbook/migrate-to-wifi.ps1

@@ -0,0 +1,43 @@
+# migrate-to-wifi.ps1 - Invoked by FlatUnattendW10-shopfloor.xml as Order 5
+# during first logon, right after wait-for-internet.ps1 and right before
+# GCCH enrollment. Moves the machine off wired onto WiFi for the rest of
+# the imaging chain so the PXE ethernet cable can be safely disconnected.
+#
+# Gated: if there is no physical Wi-Fi adapter on the machine (tower /
+# desktop case), the whole migration is a no-op. Previously this step
+# disabled all wired adapters unconditionally and then waited for WiFi
+# internet that could never arrive on towers, hanging first logon forever.
+
+$wifi = Get-NetAdapter -Physical -ErrorAction SilentlyContinue |
+        Where-Object { $_.InterfaceDescription -match 'Wi-Fi|Wireless' }
+
+if (-not $wifi) {
+    Write-Host 'No WiFi adapter - staying on ethernet.' -ForegroundColor Cyan
+    exit 0
+}
+
+Get-NetAdapter -Physical |
+    Where-Object { $_.InterfaceDescription -notmatch 'Wi-Fi|Wireless' } |
+    Disable-NetAdapter -Confirm:$false
+
+$deadline = (Get-Date).AddMinutes(5)
+$ok = $false
+while ((Get-Date) -lt $deadline) {
+    try {
+        if (Test-NetConnection -ComputerName login.microsoftonline.us -Port 443 -InformationLevel Quiet -WarningAction SilentlyContinue) {
+            $ok = $true
+            break
+        }
+    } catch {}
+    Start-Sleep -Seconds 5
+}
+
+if ($ok) {
+    Write-Host 'Internet confirmed over WiFi.' -ForegroundColor Green
+} else {
+    Write-Host 'WiFi internet timeout - re-enabling ethernet.' -ForegroundColor Yellow
+    Get-NetAdapter -Physical |
+        Where-Object { $_.InterfaceDescription -notmatch 'Wi-Fi|Wireless' } |
+        Enable-NetAdapter -Confirm:$false
+}
+exit 0