Improved concrete expansion and builder clearance

I gave the starter Core a twelve-cell concrete pad and tightened how a base expands from it. New slabs connect to friendly completed concrete instead of becoming scattered independent islands.

I also improved builder clearance around construction. The development checks cover engineers moving clear of their work and the conversion of older foundations into the connected-pad rules.

“The Core gets an initial pad, new slabs connect to existing concrete, and builders can walk clear of their work.”

The clips use the actual starter-kit deployment and inspect its native pad and Core construction blueprint. They show the starting foundation layout; they do not show a finished Core or replay the separate builder-clearance test.