Clipping support for video and audio assets

FastPix supports clipping for both video and audio media. The same clipping flow handles either type — you provide the source media along with start and end timestamps, and FastPix produces a new media asset bounded by that window. This is useful for podcast workflows, AI summary pipelines, accessibility transcription, and republishing portions of long-form content.

Clipping uses consistent start/end time semantics regardless of whether the source is video or audio, so existing clip workflows continue to apply unchanged.