Windows: full-range imported video is drawn as limited range, clipping shadows and highlights #1531

On Windows, the decoders ignore the colour range of imported footage. A full-range (AVCOL_RANGE_JPEG) video tagged with a plain yuv* pixel format is drawn as limited range, so its shadows and highlights clip in both preview and export.

Where

• crates/compositor/src/cpu_frames_windows.rs, ensure_sws: sws_getContext gets only the pixel format, never the frame's color_range, so swscale treats yuv420p / yuv420p10le as limited and copies full-range values as they are. Only the yuvj* formats are converted.
• crates/compositor/src/shaders.hlsl, yuv709_limited: the NV12 shader always reads limited range.
• The D3D11VA path passes the decoder's NV12 surface to the same shader, so full-range 8-bit H.264 is affected too.

Already true on main for AV1 and VP9 on CpuFrames, for every H.264 stream when the GPU backend is Cpu, and for full-range 8-bit H.264 on D3D11VA. OpenScreen's own recordings are tagged limited range (#923), so only imported files are concerned.

Possible fix: pass the frame's range to swscale (sws_setColorspaceDetails with srcRange from frame->color_range, dstRange limited), and normalise the hardware path the same way or pass the range to the shader.

Found during the review of #1530 (#1530 (comment)).