Explain penultimate layer choice for trigger extraction

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

paper.tex

@@ -63,7 +63,9 @@ input tokens. Weights never modified.
 \textbf{Reflex bank}: stores (trigger, response) pairs:
 \begin{itemize}
 \item \textbf{Trigger}: hidden-state vector $\mathbf{h}$ at the final token
-  position---the model's activation pattern for a given input.
+  position, extracted from the penultimate layer ($N{-}1$). The final layer is
+  optimized for next-token prediction via the lm\_head projection; earlier layers
+  retain richer semantic structure for similarity matching.
 \item \textbf{Response}: per-position logit biases
   $\{(t_i, b_i)\}$---one pair per answer token.
 \end{itemize}