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-target.ps1

@@ -0,0 +1,38 @@
+# Shared by the build, diagnostics, staging and game package scripts.
+function Get-D4RGpuTargets {
+    $registry=Join-Path $PSScriptRoot 'gpu-targets.json'
+    if (!(Test-Path -LiteralPath $registry)) { $registry=Join-Path $PSScriptRoot '../../tools/windows/gpu-targets.json' }
+    $data=Get-Content -LiteralPath $registry -Raw | ConvertFrom-Json
+    if ($data.schema -ne 1) { throw 'Unsupported GPU target registry schema.' }
+    return $data.targets
+}
+function Get-D4RGpuTargetInfo([string]$Target) {
+    $info=@(Get-D4RGpuTargets | Where-Object { $_.architecture -eq $Target })
+    if ($info.Count -ne 1) { throw "Unsupported GPU target: $Target" }
+    return $info[0]
+}
+function Get-D4RGpuTarget([string]$Root, [string]$Requested) {
+    $configured=$null
+    $targetFile=Join-Path $Root 'gpu-target.json'
+    if (Test-Path -LiteralPath $targetFile) {
+        $configured=(Get-Content -LiteralPath $targetFile -Raw | ConvertFrom-Json).architecture
+        [void](Get-D4RGpuTargetInfo $configured)
+    }
+    $target=if ($Requested) { $Requested } elseif ($configured) { $configured } else { 'gfx1201' }
+    [void](Get-D4RGpuTargetInfo $target)
+    if (!$configured -and $target -ne 'gfx1201') { throw "A $target build requires gpu-target.json; rebuild with -GpuArch $target." }
+    if ($configured -and $target -ne $configured) { throw "Requested $target differs from package target $configured" }
+    return $target
+}
+function Assert-D4RCodeObjectTarget([string]$Path, [string]$Target) {
+    $info=Get-D4RGpuTargetInfo $Target
+    $reader=[IO.BinaryReader]::new([IO.File]::OpenRead($Path))
+    try { $header=$reader.ReadBytes(64) } finally { $reader.Dispose() }
+    if ($header.Length -ne 64 -or $header[0] -ne 127 -or $header[1] -ne 69 -or $header[2] -ne 76 -or $header[3] -ne 70 -or
+        $header[4] -ne 2 -or $header[5] -ne 1 -or $header[18] -ne 224 -or $header[19] -ne 0) {
+        throw "Invalid AMDGPU ELF64 code object: $Path"
+    }
+    # LLVM AMDGPU e_flags machine IDs; inspect, never patch or spoof them.
+    $expected=$info.elfMachine
+    if ($header[48] -ne $expected) { throw "Code object does not target ${Target}: $Path (ELF machine=$($header[48]))" }
+}