Eval runner

Common skill stub — the procedure lives in .claude/commands/architect/_common/evaluator.md. Execute that file's steps with this variant binding:

• VARIANT = aflow
• VARIANT_DIR = .claude/commands/architect/aflow/
• CONFIG = <VARIANT_DIR>/config.yaml § evaluator:

Variant-specific values (profile key, side-effect artifacts) come from the config — do not duplicate them here. The evaluator is method-free: aflow's bootstrap CI + fitness_str + bare numeric score (= bootstrap median, consumed by select_round softmax) are produced in loop.md's Atomic Writer, not here.