add: base vs tuned comparison cell for V4.2 final evaluation

feat(rewards): add sentiment mismatch penalty to prevent extraction reward hacking

fix(probe): use TRL 0.24.0 log keys — rewards/commerce_reward_fn/mean, grad_norm (not train/ prefix)

fix(classifier): reorder _classify_task_type — insights before push to prevent reengajamento misclassification

fix(rewards): 3 bugs from Cell 8 audit — push length/formal, SQL domain, extraction int check

Fix V4.2 audit: show INPUT REVIEW alongside MODEL OUTPUT for proper human scoring

Fix V4.2: task weights 40/40/10/10, full audit completions, interactive input() scoring

Fix V4.2: GDPO + IWU now active in training reward path (not just monitoring)

Add V4.2 GRPO training notebook (Gold Standard, 0.5B)

notebooks: add V4.1 GRPO notebook (parser fix, 600 steps, LR 5e-6, constant_with_warmup)

v4: ROOT CAUSE FIX — use standard PEFT not Unsloth get_peft_model (fused LoRA kernels have dtype bug #4891). Revert to load_in_4bit=True, dtype=None matching V3.

v4: fix NF4 fp16/bf16 dtype bug (unsloth #4891) — load_in_4bit=False, 0.5B fits in full bf16 on 24GB

v4: fix fp16/bf16 mismatch — disable Unsloth gradient checkpointing (causes dtype conflict in LoRA QKV kernels at 0.5B)

v4 notebook: fix dtype Half/BFloat16 mismatch (explicit bf16), fix tied embeddings path, fix max_length warning

v4 notebook: fix TypeError crash, suppress warnings, update paths to CWD, add V3 task-aware system prompts

Fix total_mem → total_memory in V4 notebook (PyTorch API)

Add V4 Instruct-Only GRPO notebook implementing ADR-002

apply v3 task-aware thinking controls and delete deprecated notebook

Upload grpo_vertex_v3.ipynb

Rename notebooks/grpo_vertex_v3.ipynb to notebooks/DEPRECATED_grpo_vertex_v3.ipynb

feat: add v3 notebook (.ipynb) — ready for Vertex AI Workbench