feat(client): HDR pass-through on the D3D11VA path

A PQ stream on the D3D11VA backend was always tone-mapped to sRGB by the
VideoProcessor — with D3D11VA now auto's first choice on Intel (40030e90),
Intel Windows users would have lost HDR entirely. When the presenter can
import an RGB10A2 D3D11 texture AND offers an HDR10 swapchain (the new
VulkanDecodeDevice::d3d11_hdr10 probe), the hand-off ring switches to
RGB10A2 and the VideoProcessor does a pure colorspace conversion (YCbCr
G2084 -> RGB G2084, no tone mapping); the emitted frame carries PQ/BT.2020
color, so the presenter flips its HDR10 swapchain and video image exactly
as it does for Vulkan Video PQ frames, and the blit passes the PQ values
through untouched. SDR-only paths keep the tonemap-to-sRGB BGRA8 ring;
in-band PQ flips rebuild the ring like a resize (generation-bumped).

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

crates/pf-presenter/src/vk/present.rs

@@ -239,11 +239,12 @@ impl Presenter {
                 );
             }
 
-            // D3D11 frame: acquire the imported BGRA texture from the external "queue
+            // D3D11 frame: acquire the imported RGB texture from the external "queue
             // family" (the keyed mutex on the submit is the actual cross-API sync) and
-            // blit it into the video image — the frame arrives as ready sRGB from the
-            // decoder's VideoProcessor, so there is no CSC pass; the blit converts the
-            // BGRA→RGBA component order. Same layout dance as the CPU staging path.
+            // blit it into the video image — the frame arrives as ready RGB from the
+            // decoder's VideoProcessor (sRGB BGRA8, or PQ RGB10A2 on the HDR ring —
+            // matching the HDR-mode video image), so there is no CSC pass; the blit
+            // converts component order. Same layout dance as the CPU staging path.
             #[cfg(windows)]
             if let (Some(f), Some(v)) = (&win_frame, &self.video) {
                 external_acquire_barrier(&self.device, self.cmd_buf, f.image(), self.qfi);