Keep the ComfyUI workflow in saved videos and sharing exports (0.2.2)

[KBRASK]

Fixes #64.

Dropping a FreeVideo video on the ComfyUI canvas did nothing, so a result could not restore its workflow or be compared with another run's settings. The workflow was only saved as workflow.json next to the video. Release 0.2.2.

Saved videos

• After a successful generation the MP4 is remuxed, with streams copied rather than re-encoded. The prompt and workflow are written as QuickTime metadata keys, with moov first.
• This is the layout ComfyUI's own video nodes write and its frontend reads when a file is dropped on the canvas.
• --disable-metadata is respected. The file is rewritten before the result cache records its size and hash. Any failure keeps the original video.

Sharing exports

• The sharing video carries the same metadata. The sharing image gets it as PNG tEXt chunks, the way ComfyUI saves images.
• Videos saved before this change use the workflow.json next to them.
• The export cache key moves to v2, so earlier exports without the workflow are made again.

Checks

• New tests: tags in the place the frontend reads, moov before mdat, packets byte-identical, failures keep the file. The bridge, result cache, library and release notes tests pass.
• Sharing browser test, in both languages, with a real video: the image and video exports carry the workflow, and the original is unchanged.
• On the Windows test machine:
  • ComfyUI's PyAV 19 rewrote a copy of a real output.
  • Dropping that copy on ComfyUI's canvas restored the graph with the saved prompt and seed.
  • The same frontend reads the workflow from both sharing exports.

[KBRASK]

#64