Rethink `source.kind` in asset frontmatter for flexibility

[marcuswhybrow]

• source.kind may be audio, video, text, article, thesis, dissertation, newsletter, book.
• It was created with the assumption that only "interviews" where part of the site (not books, etc..)
• Now everything is being included.
• It's serving to distinquish output format, i.e. interview style vs plain text, which equates to audio/video/text vs the rest.
• And to describe the original medium (audio, video, web page, etc.)

Proposal

• source.medium being one of audio, video, text
• source.format being one of interview, article, newsletter, lecture, book, thesis, dissertation.

Or perhaps format should be rethought?

• What impact does format have on program logic, exactly?
• Does it determine discrete visual styles? e.g. a book may have a table of contents, whereas an interview has message bubbles.
• Does it aid reader to filter search queries? e.g. "I'm looking for video lectures, or books.

Needs more thought.

[marcuswhybrow]

Also source.medium would be video for a Generative Energy livestream, even though only Ray's only phoning in and we never see Ray. As a reader I want to know both things:

1. Can I see Ray
2. Can I see anything at all.