Take inspiration from YTPs; add a mode that creates sped up and slowed down copies of the carrier before finding matches

In YTPs, it's common to use sped up and slowed down audio/video clips of the source. We could do the same thing, which would add variety to the output, especially for short carriers, and increase how much the output matches the modulator. The benefit would be more noticeable at larger frame-lengths.

The specific process I'm envisioning is that copies of the carrier are made at something like 70%, 200%, and 300% speed, then a new file is created that's the original and the copies all stitched together end-to-end. I *assume* all that can be done with ffmpeg. After that, the new file is analyzed like normal.

I feel like this is within the scope of the project in a way just pitching up/down frames or vocoding the output wouldn't be, but I don't think it should be default behavior.

No files, tests, or entry points are named. Start by locating the existing carrier-analysis path and checking how media processing is handled; then determine where an optional mode could create 70%, 200%, and 300% carrier copies, stitch them with the original, and pass the result through normal analysis. Done means the mode is opt-in and the combined carrier is analyzed successfully.

Written by the indexing model from the issue text.