feat(android): swap MLKit Pose to the Accurate detector
Same API, higher-quality detector. Swaps the gradle artifact from
pose-detection to pose-detection-accurate and updates both pose-client
call sites to use AccuratePoseDetectorOptions. Trades ~2× per-frame
latency for materially better recall — worthwhile given pose is not
the FPS bottleneck in BOTH mode.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>