Previous version ran all 7 claude sessions in the main working tree on
branch 'architecture'. That would race on git operations and cross-
contaminate commits between languages even though their file scopes
don't overlap. Now each session runs in /root/rose-ash-loops/<lang> on
branch loops/<lang>, created from the current architecture HEAD.
sx-loops-down.sh gains --clean to remove the worktrees; loops/<lang>
branches stay unless explicitly deleted.
Also: second Enter keystroke after the /loop command, since Claude's
input box sometimes interprets the first newline as a soft break.