feat: add d4r inference engines and Windows parity tooling

Add native K/M/RR inference engines, HIP kernels, replay and validation
harnesses, and Windows DLSS setup and runtime support. Include GPU
profiling tools, build and packaging scripts, platform integration
patches, and implementation documentation.

scripts/windows/gpu-preflight.ps1

@@ -0,0 +1,58 @@
+# Read-only inventory before touching game files. It allocates no GPU memory
+# and executes no kernels; successful discovery is not hardware validation.
+function Invoke-D4RGpuPreflight([string]$PackageRoot, [string]$GameDirectory, [string]$Target, [string]$OutputDirectory) {
+    New-Item -ItemType Directory -Force $OutputDirectory | Out-Null
+    $result=[ordered]@{passed=$false; target=$Target; gpuWorkExecuted=$false; failure=$null}
+    try {
+        $proxy=Join-Path $GameDirectory 'd3d12.dll'
+        if (Test-Path -LiteralPath $proxy) {
+            $item=Get-Item -LiteralPath $proxy
+            $result.localD3D12=@{path=$proxy; sha256=(Get-FileHash -LiteralPath $proxy).Hash; product=$item.VersionInfo.ProductName}
+            # Identify known Vulkan/Wine proxies by their own strings. Do not
+            # load, remove or replace a third-party game DLL.
+            if ($item.Length -le 64MB -and [Text.Encoding]::ASCII.GetString([IO.File]::ReadAllBytes($proxy)) -match '(?i)vkd3d|wined3d') {
+                throw 'Local d3d12.dll identifies as vkd3d/Wine. Restore the game native D3D12 installation before using this Windows backend.'
+            }
+        }
+        $info=[Diagnostics.ProcessStartInfo]::new()
+        $info.FileName=Join-Path $PackageRoot 'd4r/d4r_gpu_inventory.exe'
+        $hip=Join-Path $PackageRoot 'd4r/hip'
+        foreach ($value in @($hip,$OutputDirectory)) { if ($value.Contains('"')) { throw 'Unsupported quote in inventory path.' } }
+        $info.Arguments='--hip-root "' + $hip + '" --output-dir "' + $OutputDirectory + '"'
+        $info.UseShellExecute=$false; $info.CreateNoWindow=$true
+        $info.EnvironmentVariables['D4R_DIAG_DIR']=$OutputDirectory
+        $info.RedirectStandardOutput=$true; $info.RedirectStandardError=$true
+        $process=[Diagnostics.Process]::new(); $process.StartInfo=$info
+        try {
+            if (!$process.Start()) { throw 'Cannot start GPU inventory.' }
+            $stdout=$process.StandardOutput.ReadToEndAsync(); $stderr=$process.StandardError.ReadToEndAsync()
+            $timedOut=!$process.WaitForExit(30000)
+            if ($timedOut) { $process.Kill(); $process.WaitForExit() }
+            $stdout.GetAwaiter().GetResult() | Set-Content (Join-Path $OutputDirectory 'gpu-inventory.stdout.log') -Encoding UTF8
+            $stderr.GetAwaiter().GetResult() | Set-Content (Join-Path $OutputDirectory 'gpu-inventory.stderr.log') -Encoding UTF8
+            $result.exitCode=$process.ExitCode
+            $result.exceptionOrExitHex='0x{0:X8}' -f [BitConverter]::ToUInt32([BitConverter]::GetBytes([int]$process.ExitCode),0)
+            if ($timedOut) { $result.timedOut=$true; throw 'HIP inventory timed out after 30 seconds.' }
+            if ($process.ExitCode) { throw "HIP inventory failed (exit $($process.ExitCode))." }
+        } finally { $process.Dispose() }
+        $inventory=Get-Content (Join-Path $OutputDirectory 'gpu-inventory.json') -Raw | ConvertFrom-Json
+        $result.inventory=$inventory
+        if ($inventory.compiledTarget -ne $Target) { throw "Inventory executable targets $($inventory.compiledTarget); package requires $Target." }
+        $matching=@($inventory.devices | Where-Object { $_.architecture -eq $Target -and $_.wavefrontSize -eq 32 })
+        if (!$matching.Count) {
+            $actual=@($inventory.devices | ForEach-Object { "$($_.architecture) ($($_.name))" }) -join ', '
+            throw "GPU target mismatch: detected $actual; package requires $Target. Use the package for the actual HIP architecture; do not rename code objects."
+        }
+        $result.passed=$true
+        Write-Host "D4R_PREFLIGHT target=$Target devices=$($matching.Count) gpu_work_executed=0"
+    } catch {
+        $result.failure=$_.Exception.Message
+        $result | ConvertTo-Json -Depth 8 | Set-Content (Join-Path $OutputDirectory 'preflight.json') -Encoding UTF8
+        try { Get-CimInstance Win32_VideoController | Select-Object Name,DriverVersion,DriverDate | ConvertTo-Json |
+            Set-Content (Join-Path $OutputDirectory 'driver.json') -Encoding UTF8 } catch {}
+        $bundle=$OutputDirectory+'.zip'
+        Compress-Archive -Path (Join-Path $OutputDirectory '*') -DestinationPath $bundle -Force
+        throw "$($result.failure) Diagnostic bundle: $bundle"
+    }
+    $result | ConvertTo-Json -Depth 8 | Set-Content (Join-Path $OutputDirectory 'preflight.json') -Encoding UTF8
+}