Phase 8D: universal deployment package (XP + Win10/11, two entry points)

One RIOJoy-<ver>.zip now deploys on both OS generations (~75 MB with the
offline XP prerequisites):
- Layout: RIOJoy\app (net48 x64) + RIOJoy\app-xp (net40 x86) +
  RIOJoy\vendor (ViGEmBus; vendor\xp: .NET 4.0 offline installer +
  KB2468871, both signature-verified; RioGamepadXP driver slots in when
  8B lands - build warns/skips until then).
- RIOJoy\install-core.bat: shared OS-detecting install logic (ver ->
  5.1 = XP); pure cmd.exe on the XP path, delegates to install-rio.ps1
  on 10/11. Exports RIOJOY_APPDIR for shortcut creation.
- postinstall.bat (TeslaConsole, unattended): elevates, runs the core,
  then deletes install.bat + README.txt so C:\games stays clean.
- install.bat (standalone computers): same core + Start Menu/desktop
  shortcuts via make-shortcut.vbs (XP-safe); keeps the README.
- README.txt at the zip root explains which entry point to run.
- deploy *.ps1 re-encoded UTF-8-with-BOM: Windows PowerShell read the
  BOM-less files as ANSI, where an em-dash byte parses as a curly quote
  and breaks string parsing (bit install-rio.ps1 in dry-run testing).

Verified: zip layout correct; extracted package dispatch-tested on
Win10 non-elevated (OS detect -> modern route -> admin guard, system
untouched).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

deploy/install-rio.ps1

@@ -1,4 +1,4 @@
-<#
+<#
 .SYNOPSIS
     RIOJoy cockpit post-install. Installs the signed ViGEmBus virtual-controller
     driver (if absent). Must run elevated (postinstall.bat elevates for you).