Offset PE nodes in cube_view to avoid overlapping routers

PE nodes are shifted 1.2mm above (top half) or below (bottom half)
their assigned router position. PE size reduced to 1.4x0.7mm.

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

src/kernbench/topology/visualizer.py

@@ -157,7 +157,7 @@ def _compute_node_sizes(
         w_mm, h_mm = _KIND_SIZE.get(node.kind, (_DEFAULT_NODE_W, _DEFAULT_NODE_H))
         # For cube view, use smaller PE nodes
         if view.name == "cube" and node.kind == "pe":
-            w_mm, h_mm = 1.8, 1.0
+            w_mm, h_mm = 1.4, 0.7
         if view.name == "pe":
             w_mm, h_mm = 2.5, 1.4
         sizes[nid] = (w_mm * scale, h_mm * scale)