style(#1532): Lookup renders as a gray Manual-sized rectangle

Match Lookup's box size to Manual (fontsize/size), so a Lookup reads as a gray
rectangle the same size as a Manual table rather than a smaller subtle box. Part
rendering unchanged (neutral subtle box, per design review).

Author: dimitri-yatsenko

src/datajoint/diagram.py

@@ -54,7 +54,7 @@
 _TIER_STRUCTURE = {
     None: dict(shape="circle", fontsize=round(_scale * 8), size=0.4 * _scale, fixed=False, rounded=False),
     Manual: dict(shape="box", fontsize=round(_scale * 10), size=0.4 * _scale, fixed=False, rounded=True),
-    Lookup: dict(shape="box", fontsize=round(_scale * 8), size=0.4 * _scale, fixed=False, rounded=True),
+    Lookup: dict(shape="box", fontsize=round(_scale * 10), size=0.4 * _scale, fixed=False, rounded=True),
     Computed: dict(shape="ellipse", fontsize=round(_scale * 10), size=0.4 * _scale, fixed=False, rounded=False),
     Imported: dict(shape="ellipse", fontsize=round(_scale * 10), size=0.4 * _scale, fixed=False, rounded=False),
     Part: dict(shape="box", fontsize=round(_scale * 8), size=0.1 * _scale, fixed=False, rounded=True),