Feature: Downsample videos

Create the ability to downscale and sample video files. Create lower resolution and time limited previews that are significantly smaller in size and can be easier shared with various applications and platforms.

Leverage ffmpeg to downscale videos to e.g. 720p, lower frame rates and quality and limit to the first 30 sec of any video. Place preview samples in dedicated preview folder structure.

No files, tests, or entry points are named. Start by locating the existing video-processing workflow and any ffmpeg integration, then determine how output folders are organized. Done means generating 720p-or-lower, lower-quality previews limited to the first 30 seconds and placing them in a dedicated preview structure.

Written by the indexing model from the issue text.