Dead code: `if !true { ... }` is a permanently-disabled guard pattern.
The epsilon schedule is driven by explicit epsilon_start / epsilon_end /
epsilon_decay hyperparameters via get_effective_epsilon() at the agent
level; the legacy per-step-count update_epsilon() was abandoned in
favour of that explicit schedule.
Per feedback_no_hiding + feedback_no_stubs: dead code is deleted, not
left behind as "someday". Per feedback_no_feature_flags: a !true toggle
is a disabled feature flag pattern.
Zero behavior change; removes foot-gun.