cleanup: remove stale dev/abandoned files

GRPO run3 held_out_eval (200 steps)

GRPO run3 log_history (200 steps)

GRPO run3 trainer_state (200 steps)

GRPO Run #1 held-out eval (80 clips)

add Pivot Set candidates (filter output)

add Prosody-Pivot Set (32 confidently-wrong clips: 7 sarc + 25 sinc)

add text-only Qwen baseline (curate_pivot_set baseline)

Upload folder using huggingface_hub