CVE-2026-65970: OpenImageIO: TIFF multithreaded scanline read use-after-scope in `TIFFInput::read_native_scanlines`

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.1.16.0, a crafted ZIP-compressed TIFF processed with TIFF multithreading enabled can make TIFFInput::readnativescanlines() return through an error path while asynchronous strip-decompression work remains queued. Because taskset is declared before ok and compressedscratch, those captured objects are destroyed before the task-set destructor waits, allowing worker tasks to use stale stack and heap storage, resulting in a use-after-scope crash and denial of service. The affected implementation is identified by src/tiff.imageio/tiffinput.cpp, TIFFInput::readnativescanlines(), taskset, ok, compressedscratch, and uncompressonestrip(), which define the relevant source path, functions, state, and trigger. This issue is fixed in 3.1.16.0.