Fixed
Anamorphic scrub-preview / chapter thumbnails rendered horizontally stretched (#23)
FrameExtractor, the on-device frame source for scrub previews and chapter thumbnails, scaled each decoded frame using its coded width and height only and ignored the sample aspect ratio. An NTSC DVD (720x480 stored, displayed at 4:3) therefore produced a 3:2 thumbnail, which hosts then drew too wide.
FrameDecodeContext now reads the stream SAR at open (with the per-frame SAR as a fallback, since the software decoder does not reliably attach it) and folds it into the output height, so thumbnails keep the source display aspect: 4:3 for standard DVDs, 16:9 for anamorphic widescreen DVDs. This mirrors the main decode-path SAR fix shipped in 3.11.3.
The HDR tone-map thumbnail path is unchanged, since anamorphic content is effectively always SDR. A regression test covers NTSC (8:9), PAL (16:15 and BT.601 12:11), anamorphic widescreen (32:27), square pixels, and a degenerate SAR.
Reported by @cstark27. Thanks for the detailed follow-up.
Full changelog: https://github.com/superuser404notfound/AetherEngine/blob/main/CHANGELOG.md
