startnet.cmd: stage udc-backups to WinPE; mirror-from-gold: taxonomy layout

- playbook/startnet.cmd + startnet-template.cmd: after preinstall staging,
  xcopy Y:\pre-install\udc-backups to W:\PreInstall\udc-backups so UDC
  settings JSONs are available during image deployment. Harvested from
  live gold where this block existed but was never committed.

- scripts/mirror-from-gold.sh: update source paths to current taxonomy
  layout (pre-install/, installers-post/, blancco/, config/) and add
  ppkgs/, scripts/, shopfloor-setup/ sections. Added --delete for exact
  mirror semantics. Used to seed the spare PXE server at 10.9.100.2 on
  2026-04-16 from gold at 10.9.100.1.

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

playbook/startnet.cmd

@@ -332,6 +332,10 @@ if exist "Y:\pre-install\preinstall.json" (
     ) else (
         echo WARNING: Y:\pre-install\installers not found - preinstall.json staged without installers.
     )
+    if exist "Y:\pre-install\udc-backups" (
+        xcopy /E /Y /I "Y:\pre-install\udc-backups" "W:\PreInstall\udc-backups\"
+        echo Staged UDC settings backups to W:\PreInstall\udc-backups.
+    )
 ) else (
     echo No preinstall bundle on PXE server - skipping.
 )