New _reference_metrics() computes LSD, MCD, and per-band correlation
between eval samples and the original source audio at each checkpoint.
Loads reference audio once before the training loop and logs metrics
alongside existing spectral metrics.
Also fix batch_size in lora_optimized_dataset.json (4 -> 16).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Replace all BJ references with generic "target style/audio" in
activation steering, DITTO optimizer, and BigVGAN trainer
- Add latent_mixup_alpha/latent_noise_sigma to LoRA scheduler defaults
- Add bigvgan_disc_fm_retest.json and lora_optimized_dataset.json
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>