Distinguish manual vs auto-generated transcripts in metadata

I want the `transcriptLanguages` array in the metadata response to include a 'type' or 'isGenerated' flag for each language. Currently, it only provides language codes, making it impossible to know which transcripts are manually uploaded versus auto-generated/translated. This forces me to iterate through dozens of languages using `mode=native` to find a valid one without triggering expensive AI generation costs. Having a way to distinguish these in the metadata would allow me to target only manual transcripts efficiently.