Load workflows from mp4/mov files

[christian-byrne]

Resolves #3538 by supporting loading workflows from mp4 files. Also allows parsing .mov and .m4v, should they later be created as outputs by ComfyUI or custom nodes.

The MP4 file format was originally based on the QuickTime File Format (.mov), later evolving to MP4 v2 as MPEG-4, then finally generalized into the ISO base media file format (ISOBMFF). This created a broader standard used as the foundation for multiple container formats, including modern .mov and related types like .m4v (often used for MP4 video within Apple ecosystems). ISOBMFF is a container file format that "defines a general structure for files that contain time-based multimedia data such as video and audio."

To embed metadata from the python side, use the following approach:

        # Create container with movflags option
        container = av.open(temp_path, mode='w', options={'movflags': 'use_metadata_tags'})
        
        # Add metadata
        if prompt is not None:
            container.metadata["prompt"] = json.dumps(prompt)
        
        if extra_pnginfo is not None:
            for x in extra_pnginfo:
                container.metadata[x] = json.dumps(extra_pnginfo[x])

┆Issue is synchronized with this Notion page by Unito

[christian-byrne]

In future: refactor this entire section of app.ts that conditionally handles dropped files based on type/extension. It is repeating same logic for every file type and the number of supported output types if increasing