run-solo-bench.sh runs the builder-solo variant (single builder, self-verify,
no adversary) 5× on the same calculator and appends rows to the shared campaign
data file (adversary col = 0). Separate script so the live campaign runner is
untouched. analyze.py limit-detection now also covers the solo run layout.
Engine example builder-solo committed at a0f7652; benchmark engine to be re-
pinned to it before running solo (after the main campaign completes).
