4-phase plan from deep audit: critical bug fixes (weight_decay, IQN PER, q_value_std, 54/51 dim mismatch), train/eval parity (TradeExecutor, checkpoint validation), SOTA improvements (differential Sharpe, PQN LayerNorm, temporal PER, dormant neuron resets), and search space cleanup. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>