Keep the ablation arms inside the line budget the repo enforces

copy_store() moved into bench/scratch.py: systems.py had reached 512 lines
and bench/filesize_check fails anything over 500. The move is behaviour
identical, so the scale reports keep the commit stamp they were generated
against — the code they describe is complete at that commit.

bench/term_sweep.py

@@ -20,7 +20,8 @@ from bench.metrics import aggregate, score_query
 from bench.query_set import load_queries, scale_probes
 from bench.report import git_commit
 from bench.run import latency
-from bench.systems import copy_store, live_product_rankings, machine_facts
+from bench.scratch import copy_store
+from bench.systems import live_product_rankings, machine_facts
 
 FRACTIONS = [0.20, 0.10, 0.05, 0.02, 0.01, 0.005]
 TOP_K = 10