feat(encode): native QSV backend — libvpl-sys + qsv.rs (Phases 0-3 of design/native-qsv-encoder.md)

Vendored MIT VPL dispatcher (static, trimmed tree, pin 674d015b/v2.17.0) built
via cmake+bindgen behind new feature 'qsv' (pf-encode + punktfunk-host forward).
qsv.rs: dispatcher session on the capture adapter (LUID-matched), SetHandle
D3D11, AsyncDepth=1/GopRefDist=1/VDEnc/CBR + HRD-off low-latency config,
GetSurfaceForEncode + GPU CopySubresourceRegion input (zero-copy, no readback
path), bounded sync-point poll, in-place reset with teardown escalation, no-IDR
bitrate retarget (Reset + StartNewSequence=OFF), 10-bit P010 HEVC-Main10/AV1,
HDR mastering/CLL SEI-OBU at IDR + BT.2020/PQ VSI, LTR-RFI via mfxExtRefListCtrl
(AMF slot policy port, Query-gated per codec, wire-index FrameOrder pinning).
Dispatch: native-first with ffmpeg fallback + PUNKTFUNK_QSV_FFMPEG hatch;
probes (can_encode_10bit / windows_codec_support / windows_backend_is_probed)
now answer natively for QSV.

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

crates/libvpl-sys/vendor/libvpl/api/vpl/mfxmvc.h

@@ -0,0 +1,105 @@
+/*############################################################################
+  # Copyright Intel Corporation
+  #
+  # SPDX-License-Identifier: MIT
+  ############################################################################*/
+
+#ifndef __MFXMVC_H__
+#define __MFXMVC_H__
+
+#include "mfxdefs.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* CodecProfile, CodecLevel */
+enum {
+    /* MVC profiles */
+    MFX_PROFILE_AVC_MULTIVIEW_HIGH = 118, /*!< Multi-view high profile. The encoding of VDEnc or LowPower ON is not supported. */
+    MFX_PROFILE_AVC_STEREO_HIGH    = 128  /*!< Stereo high profile. The encoding of VDEnc or LowPower ON is not supported. */
+};
+
+/* Extended Buffer Ids */
+enum {
+    MFX_EXTBUFF_MVC_SEQ_DESC     =   MFX_MAKEFOURCC('M','V','C','D'), /*!< This extended buffer describes the MVC stream information of view dependencies, view identifiers, and operation points. See the ITU*-T H.264 specification chapter H.7.3.2.1.4 for details. */
+    MFX_EXTBUFF_MVC_TARGET_VIEWS =   MFX_MAKEFOURCC('M','V','C','T')  /*!< This extended buffer defines target views at the decoder output.*/
+};
+
+MFX_PACK_BEGIN_USUAL_STRUCT()
+/*!
+  Describes MVC view dependencies.
+*/
+typedef struct  {
+    mfxU16 ViewId; /*!< View identifier of this dependency structure. */
+
+    mfxU16 NumAnchorRefsL0; /*!< Number of view components for inter-view prediction in the initial reference picture list RefPicList0 for anchor view components. */
+    mfxU16 NumAnchorRefsL1; /*!< Number of view components for inter-view prediction in the initial reference picture list RefPicList1 for anchor view components. */
+    mfxU16 AnchorRefL0[16]; /*!< View identifiers of the view components for inter-view prediction in the initial reference picture list RefPicList0 for anchor view components. */
+    mfxU16 AnchorRefL1[16]; /*!< View identifiers of the view components for inter-view prediction in the initial reference picture list RefPicList1 for anchor view components. */
+
+    mfxU16 NumNonAnchorRefsL0; /*!< Number of view components for inter-view prediction in the initial reference picture list RefPicList0 for non-anchor view components. */
+    mfxU16 NumNonAnchorRefsL1; /*!< Number of view components for inter-view prediction in the initial reference picture list RefPicList1 for non-anchor view components. */
+    mfxU16 NonAnchorRefL0[16]; /*!< View identifiers of the view components for inter-view prediction in the initial reference picture list RefPicList0 for non-anchor view components. */
+    mfxU16 NonAnchorRefL1[16]; /*!< View identifiers of the view components for inter-view prediction in the initial reference picture list RefPicList0 for non-anchor view components. */
+} mfxMVCViewDependency;
+MFX_PACK_END()
+
+MFX_PACK_BEGIN_STRUCT_W_PTR()
+/*!
+  Describes the MVC operation point.
+*/
+typedef struct {
+    mfxU16 TemporalId;     /*!< Temporal identifier of the operation point. */
+    mfxU16 LevelIdc;       /*!< Level value signaled for the operation point. */
+
+    mfxU16 NumViews;       /*!< Number of views required for decoding the target output views that correspond to the operation point. */
+    mfxU16 NumTargetViews; /*!< Number of target output views for the operation point. */
+    mfxU16 *TargetViewId;  /*!< Target output view identifiers for operation point. */
+} mfxMVCOperationPoint;
+MFX_PACK_END()
+
+MFX_PACK_BEGIN_STRUCT_W_PTR()
+/*!
+  Describes the MVC stream information of view dependencies, view identifiers, and operation points. See the ITU*-T H.264 specification chapter H.7.3.2.1.4 for details.
+*/
+typedef struct  {
+    mfxExtBuffer Header;        /*!< Extension buffer header. Header.BufferId must be equal to MFX_EXTBUFF_MVC_SEQUENCE_DESCRIPTION. */
+
+    mfxU32 NumView;             /*!< Number of views. */
+    mfxU32 NumViewAlloc;        /*!< The allocated view dependency array size. */
+    mfxMVCViewDependency *View; /*!< Pointer to a list of the mfxMVCViewDependency. */
+
+    mfxU32 NumViewId;           /*!< Number of view identifiers. */
+    mfxU32 NumViewIdAlloc;      /*!< The allocated view identifier array size. */
+    mfxU16 *ViewId;             /*!< Pointer to the list of view identifier. */
+
+    mfxU32 NumOP;               /*!< Number of operation points. */
+    mfxU32 NumOPAlloc;          /*!< The allocated operation point array size. */
+    mfxMVCOperationPoint *OP;   /*!< Pointer to a list of the mfxMVCOperationPoint structure. */
+
+    mfxU16 NumRefsTotal;        /*!< Total number of reference frames in all views required to decode the stream. This value is returned from the MFXVideoDECODE_Decodeheader function. Do not modify this value. */
+    mfxU32 Reserved[16];
+
+} mfxExtMVCSeqDesc;
+MFX_PACK_END()
+
+MFX_PACK_BEGIN_USUAL_STRUCT()
+/*!
+ Configures views for the decoding output.
+*/
+typedef struct {
+    mfxExtBuffer    Header; /*!< Extension buffer header. Header.BufferId must be equal to MFX_EXTBUFF_MVC_TARGET_VIEWS. */
+
+    mfxU16 TemporalId;      /*!< The temporal identifier to be decoded. */
+    mfxU32 NumView;         /*!< The number of views to be decoded. */
+    mfxU16 ViewId[1024];    /*!< List of view identifiers to be decoded. */
+} mfxExtMVCTargetViews ;
+MFX_PACK_END()
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif
+