v0.9.0-dev.9

fix(build): disable MTMD_VIDEO across all native builds

The d6d0ce82 bump pulled in mtmd video decoding, which #includes
vendor/sheredom/subprocess.h and calls posix_spawn to launch ffmpeg. That
broke the Android CPU AAR build (posix_spawn isn't in the NDK at API 26),
and the feature is useless in every target we ship (it needs an ffmpeg
binary in PATH at runtime). MTMD_VIDEO defaults ON upstream; force it OFF
in all four build scripts. Only the mtmd_helper_video_* path drops out;
the bitmap-init symbols the binding uses are unaffected.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>