Update architecture docs with state persistence and uncertainty

docs/architecture.md

@@ -37,6 +37,8 @@ Grid-JEPA combines JEPA self-supervised learning with world model dynamics for A
 - GRU sequence model
 - Discrete latent encoder with straight-through gradients
 - Imagination rollouts for planning
+- **CRITICAL: State persists across levels within an environment** — Level 3 requires knowledge from Level 1-2
+- Uncertainty-aware prediction for hypothesis revision (when predictions fail, update the model)
 
 ## 4. Hierarchical Controller