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-core.bat

@@ -0,0 +1,68 @@
+@echo off
+rem ===========================================================================
+rem  RIOJoy shared install core - called by postinstall.bat (cabinet /
+rem  TeslaConsole) and install.bat (freestanding). NOT run directly.
+rem  Detects the OS and installs the matching flavor's prerequisites:
+rem    Windows XP (5.1)   -> .NET 4.0 + KB2468871 from RIOJoy\vendor\xp,
+rem                          RioGamepadXP driver INF when bundled;
+rem                          app = RIOJoy\app-xp (net40 x86)
+rem    Windows 10/11      -> RIOJoy\install-rio.ps1 (ViGEmBus etc.);
+rem                          app = RIOJoy\app (net48 x64)
+rem  Pure cmd.exe on the XP path (XP has no in-box PowerShell). Idempotent.
+rem  Sets RIOJOY_APPDIR for the caller (shortcut creation).
+rem ===========================================================================
+setlocal EnableExtensions
+set CORE_RC=0
+set PKGROOT=%~dp0
+rem PKGROOT = ...\RIOJoy\ (this file lives inside the payload folder)
+
+ver | findstr /C:"Version 5.1" >nul
+if %errorlevel% equ 0 goto xp
+
+rem --- Windows 10/11 ---------------------------------------------------------
+echo Detected modern Windows - installing the net48 x64 flavor prerequisites.
+powershell -NoProfile -ExecutionPolicy Bypass -File "%PKGROOT%install-rio.ps1"
+set CORE_RC=%errorlevel%
+endlocal & set "RIOJOY_APPDIR=%~dp0app" & exit /b %CORE_RC%
+
+:xp
+rem --- Windows XP SP3 ---------------------------------------------------------
+echo Detected Windows XP - installing the net40 x86 flavor prerequisites.
+
+rem .NET Framework 4.0 (XP's ceiling; required by the app).
+reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full" /v Install 2>nul | findstr /C:"0x1" >nul
+if %errorlevel% equ 0 (
+    echo .NET Framework 4.0 already installed.
+) else (
+    if exist "%PKGROOT%vendor\xp\dotNetFx40_Full_x86_x64.exe" (
+        echo Installing .NET Framework 4.0 - this takes several minutes...
+        "%PKGROOT%vendor\xp\dotNetFx40_Full_x86_x64.exe" /q /norestart
+        if errorlevel 3011 echo .NET install requests a reboot - reboot before first use.
+    ) else (
+        echo ERROR: vendor\xp\dotNetFx40_Full_x86_x64.exe is missing from the package.
+        set CORE_RC=1
+        goto xpdone
+    )
+)
+
+rem KB2468871 - required by the async runtime (Microsoft.Bcl.Async).
+rem The update no-ops quickly when already applied, so run unconditionally.
+if exist "%PKGROOT%vendor\xp\NDP40-KB2468871-v2-x86.exe" (
+    echo Applying .NET 4.0 update KB2468871...
+    "%PKGROOT%vendor\xp\NDP40-KB2468871-v2-x86.exe" /q /norestart
+) else (
+    echo WARNING: vendor\xp\NDP40-KB2468871-v2-x86.exe not bundled - the app
+    echo          will not run without KB2468871. Install it before first use.
+)
+
+rem RioGamepadXP virtual-joystick driver (bundled from Phase 8B onward).
+if exist "%PKGROOT%vendor\xp\RioGamepadXP.inf" (
+    echo Installing the RioGamepadXP virtual joystick driver...
+    rundll32 setupapi.dll,InstallHinfSection DefaultInstall 132 %PKGROOT%vendor\xp\RioGamepadXP.inf
+) else (
+    echo Note: RioGamepadXP driver not bundled yet - joystick output is
+    echo       unavailable on XP; keyboard/mouse, lamps and plasma still work.
+)
+
+:xpdone
+endlocal & set "RIOJOY_APPDIR=%~dp0app-xp" & exit /b %CORE_RC%