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>

startnet-template.cmd

@@ -266,6 +266,8 @@ if errorlevel 1 (
     goto copy_pctype
 )
 copy /Y "Y:\run-enrollment.ps1" "W:\Enrollment\run-enrollment.ps1"
+copy /Y "Y:\wait-for-internet.ps1" "W:\Enrollment\wait-for-internet.ps1"
+copy /Y "Y:\migrate-to-wifi.ps1" "W:\Enrollment\migrate-to-wifi.ps1"
 
 REM --- Create enroll.cmd at drive root as manual fallback ---
 > W:\enroll.cmd (