fix(bench): normalize terminal-bench run ids

[drewstone]

Summary

• normalize Terminal-Bench A/B run IDs to lowercase before passing them to tb run
• avoids Docker Compose rejecting uppercase-derived project names during local A/B runs

Verification

• git diff --check
• bash -n bench/run-ab-arm.sh
• shell normalization probe: Raw-Run-ABC-123 -> raw-run-abc-123
• git merge-tree --write-tree origin/main HEAD

[tangletools]

✅ Auto-approved drewstone PR — 7d54e020

This PR was opened by the trusted drewstone account.
The full PR reviewer audit still runs separately and will publish findings if it detects issues.

_{tangletools · auto-approval · reason: drewstone_author · 2026-07-08T00:06:29Z}