Vendor media_kit_video 2.0.1 with the X11/EGL fix (hardware rendering on X11 with Flutter >= 3.38)

Flutter >= 3.38 keeps its EGL contexts on the raster thread, so
media_kit's video output found none on the platform thread and fell
back to software rendering (no shaders, ~5 fps) on X11. The patched
output opens Flutter's EGL display itself, steps GDK's GLX context aside
on X11 and releases its own context. Patch from a friend's agent, kept
in third_party/media_kit_video/starsync/. Wayland/NVIDIA still renders
on the GPU (checked); the X11 path was verified on the friend's machine.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

third_party/media_kit_video/README.md

@@ -0,0 +1,11 @@
+# [package:media_kit_video](https://github.com/media-kit/media-kit)
+
+[![](https://img.shields.io/discord/1079685977523617792?color=33cd57&label=Discord&logo=discord&logoColor=discord)](https://discord.gg/h7qf2R9n57) [![Github Actions](https://github.com/media-kit/media-kit/actions/workflows/ci.yml/badge.svg)](https://github.com/media-kit/media-kit/actions/workflows/ci.yml)
+
+Native implementation for video playback in [package:media_kit](https://pub.dev/packages/media_kit).
+
+## License
+
+Copyright © 2021 & onwards, Hitesh Kumar Saini <<saini123hitesh@gmail.com>>
+
+This project & the work under this repository is governed by MIT license that can be found in the [LICENSE](./LICENSE) file.