Add experimental packed and in-place DLSS output

- Tag redirected surfaces as R10G10B10A2 ('R3') as well as RGBA16F ('R2'), and
  let the native output kernel store the game's R10G10B10A2 texels itself.
- Import linear, exportable game textures (vkd3d-proton patch 0003) into HIP
  so the output kernel writes the game's output texture with no game-side copy.
- Add ID3D12DXVKInteropDeviceD4R3 with GetVulkanLinearImageInfo.
- Gate both paths behind D4R_SHIM_OUTPUT_PACKED and D4R_SHIM_INPLACE, and use
  them only for split frames of preset M whose output kernel honours the redirect.
- Convert on the host when a recorded packed frame finds the wrong kernel.
- Give the harness an R10G10B10A2 output, and add D4R_SHIM_SPIN_POLL so
  frame timing is not quantised to the poll sleep.
- Document the measured removal of the output copies in performance.md.

tools/d4r_win32_wait.h

@@ -9,7 +9,10 @@ inline void d4r_sleep_us(unsigned int microseconds)
     using Delay = LONG(WINAPI*)(BOOLEAN, LARGE_INTEGER*);
     static const auto delay = reinterpret_cast<Delay>(reinterpret_cast<void*>(
         GetProcAddress(GetModuleHandleW(L"ntdll.dll"), "NtDelayExecution")));
-    if (microseconds == 0)
+    // D4R_SHIM_SPIN_POLL=1 (measurement only): every poll yields instead of sleeping, so frame timings are
+    // not quantised to the ~250 us a 200 us sleep takes. Costs a CPU core per waiting thread.
+    static const bool spin = GetEnvironmentVariableA("D4R_SHIM_SPIN_POLL", nullptr, 0) > 1;
+    if (microseconds == 0 || spin)
     {
         SwitchToThread();
         return;