Add the typed event dataclasses VideoGenerator.generate_async will
emit, plus a VideoResult alias for the public docs:
* VideoProgressEvent / VideoPartialEvent / VideoFinalEvent
* VideoEvent = union of the three
* VideoResult = GenerationResult
Re-exported from fastvideo.api so the Dynamo backend package, the
streaming server, and the stateless OpenAI server share one set of
names.
Co-authored-by: Junda (David) Su <90978028+Davids048@users.noreply.github.com>
Co-authored-by: Matthew Noto <99706358+RandNMR73@users.noreply.github.com>
Co-authored-by: XOR-op <17672363+XOR-op@users.noreply.github.com>
Co-authored-by: Zhang Peiyuan <42993249+jzhang38@users.noreply.github.com>
