batch_greedy_actions, batch_softmax_actions, and
batch_hierarchical_softmax_actions all used self.forward() which routes
through the dist_dueling/dueling/standard Q-network. When use_iqn=true,
the training loss trains the IQN QuantileNetwork but inference never
consulted it — the trained IQN weights were ignored at evaluation time.
Add q_values_for_batch() helper that dispatches to the IQN network
(with CVaR or expected-Q reduction) when use_iqn=true, and wire all
three batch methods through it. select_action, select_action_with_confidence,
and select_action_inference already had correct IQN branches.
Add test_iqn_batch_greedy_actions_uses_iqn_network covering training,
batch greedy, batch softmax, and inference paths with IQN enabled.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
a442a48acd