- Add lr_schedule param (constant|cosine) to SelvaLoraTrainer
- Cosine decays LR from initial value to ~0 after warmup, preventing
the oscillation observed at steps 6000-8000 with lr=2e-4 flat
- Wire lr_schedule through scheduler _PARAM_DEFAULTS and _train_inner call
- Add g5_r128_lr_2e4_cosine and g5_r128_lr_3e4_cosine to r128_sweet_spot sweep
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
9 experiments targeting loss 0.25-0.35 without LoRA+ noise.
Tests higher base LR (2e-4/3e-4/5e-4), curriculum combos, conservative
LoRA+ ratio=4, and rank 256 baseline + lr=3e-4.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>